[WIP] Upgrade ONOS to karaf version 4.2.1

Change-Id: I7cd40c995bdf1c80f94b1895fb3344e32404c7fa
diff --git a/incubator/rpc-nb/src/main/java/org/onosproject/incubator/rpc/nb/impl/GrpcServer.java b/incubator/rpc-nb/src/main/java/org/onosproject/incubator/rpc/nb/impl/GrpcServer.java
index 8019cee..4ea8e50 100644
--- a/incubator/rpc-nb/src/main/java/org/onosproject/incubator/rpc/nb/impl/GrpcServer.java
+++ b/incubator/rpc-nb/src/main/java/org/onosproject/incubator/rpc/nb/impl/GrpcServer.java
@@ -18,11 +18,11 @@
 
 import io.grpc.Server;
 import io.grpc.netty.NettyServerBuilder;
-import org.apache.felix.scr.annotations.Activate;
-import org.apache.felix.scr.annotations.Component;
-import org.apache.felix.scr.annotations.Deactivate;
-import org.apache.felix.scr.annotations.Reference;
-import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Deactivate;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
 import org.onosproject.incubator.rpc.nb.mcast.MulticastRouteGrpcService;
 import org.onosproject.net.mcast.MulticastRouteService;
 import org.slf4j.Logger;
@@ -38,7 +38,7 @@
 
     private final Logger log = LoggerFactory.getLogger(getClass());
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected MulticastRouteService multicastRouteService;
 
     // TODO make configurable