Bump Guava to 21.0

Change-Id: Id81705773d191db6a18153d8b2dd4abd2bfd0e60
diff --git a/core/common/src/main/java/org/onosproject/common/DefaultTopology.java b/core/common/src/main/java/org/onosproject/common/DefaultTopology.java
index dd2f3a9..81822c1 100644
--- a/core/common/src/main/java/org/onosproject/common/DefaultTopology.java
+++ b/core/common/src/main/java/org/onosproject/common/DefaultTopology.java
@@ -35,7 +35,6 @@
 import org.onlab.graph.TarjanGraphSearch;
 import org.onlab.graph.TarjanGraphSearch.SccResult;
 import org.onlab.graph.Weight;
-import org.onlab.util.GuavaCollectors;
 import org.onosproject.net.AbstractModel;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.DefaultDisjointPath;
@@ -437,7 +436,7 @@
         return KSHORTEST.search(graph, srcV, dstV, weigher, maxPaths)
                 .paths().stream()
                     .map(this::networkPath)
-                    .collect(GuavaCollectors.toImmutableSet());
+                    .collect(ImmutableSet.toImmutableSet());
     }
 
     /**
diff --git a/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceDeviceListener.java b/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceDeviceListener.java
index 7ba0296..ad90f79 100644
--- a/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceDeviceListener.java
+++ b/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceDeviceListener.java
@@ -21,7 +21,6 @@
 import org.onlab.packet.MplsLabel;
 import org.onlab.packet.VlanId;
 import org.onlab.util.Bandwidth;
-import org.onlab.util.GuavaCollectors;
 import org.onlab.util.ItemNotFoundException;
 import org.onosproject.mastership.MastershipService;
 import org.onosproject.net.ChannelSpacing;
@@ -284,7 +283,7 @@
             if (query != null) {
                 return query.queryLambdas(port).stream()
                         .flatMap(ResourceDeviceListener::toResourceGrid)
-                        .collect(GuavaCollectors.toImmutableSet());
+                        .collect(ImmutableSet.toImmutableSet());
             } else {
                 return Collections.emptySet();
             }
diff --git a/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceManager.java b/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceManager.java
index 606c80d..7857e40 100644
--- a/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceManager.java
+++ b/core/net/src/main/java/org/onosproject/net/resource/impl/ResourceManager.java
@@ -23,7 +23,6 @@
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.Service;
-import org.onlab.util.GuavaCollectors;
 import org.onlab.util.Tools;
 import org.onosproject.event.AbstractListenerManager;
 import org.onosproject.net.resource.DiscreteResourceId;
@@ -133,7 +132,7 @@
         Collection<Resource> resources = store.getAllocatedResources(parent, cls);
         return resources.stream()
                 .flatMap(resource -> store.getResourceAllocations(resource.id()).stream())
-                .collect(GuavaCollectors.toImmutableList());
+                .collect(ImmutableList.toImmutableList());
     }
 
     @Override
diff --git a/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ConsistentContinuousResourceSubStore.java b/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ConsistentContinuousResourceSubStore.java
index 79aed3b..785ae31 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ConsistentContinuousResourceSubStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ConsistentContinuousResourceSubStore.java
@@ -17,7 +17,6 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
-import org.onlab.util.GuavaCollectors;
 import org.onosproject.net.resource.ContinuousResource;
 import org.onosproject.net.resource.ContinuousResourceId;
 import org.onosproject.net.resource.DiscreteResourceId;
@@ -74,7 +73,7 @@
 
         return allocations.value().allocations().stream()
                 .filter(x -> x.resource().id().equals(resource))
-                .collect(GuavaCollectors.toImmutableList());
+                .collect(ImmutableList.toImmutableList());
     }
 
     @Override
diff --git a/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ContinuousResourceAllocation.java b/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ContinuousResourceAllocation.java
index 03dc713..a14313f 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ContinuousResourceAllocation.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/resource/impl/ContinuousResourceAllocation.java
@@ -16,7 +16,6 @@
 package org.onosproject.store.resource.impl;
 
 import com.google.common.collect.ImmutableList;
-import org.onlab.util.GuavaCollectors;
 import org.onosproject.net.resource.ContinuousResource;
 import org.onosproject.net.resource.ResourceAllocation;
 import org.onosproject.net.resource.ResourceConsumerId;
@@ -93,7 +92,7 @@
 
         return new ContinuousResourceAllocation(original,
                 Stream.concat(nonMatched.stream(), matched.stream())
-                        .collect(GuavaCollectors.toImmutableList()));
+                        .collect(ImmutableList.toImmutableList()));
     }
 
     @Override