Handle Copycat queries in high priority

- Minor: use execute(..) to avoid swallowing Exceptions

Change-Id: Id543ccb1b4388c51b4507fc7cfcacf526f1f4f32
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/OnosCopycatClient.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/OnosCopycatClient.java
index 27d513a..d541bb1 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/OnosCopycatClient.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/OnosCopycatClient.java
@@ -17,6 +17,7 @@
 
 import static java.util.concurrent.Executors.newSingleThreadScheduledExecutor;
 import static org.onlab.util.Tools.groupedThreads;
+import static org.onlab.util.Tools.maxPriority;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.net.ConnectException;
@@ -63,7 +64,7 @@
         super(client);
         this.maxRetries = maxRetries;
         this.delayBetweenRetriesMillis = delayBetweenRetriesMillis;
-        this.executor = newSingleThreadScheduledExecutor(groupedThreads("OnosCopycat", "client", log));
+        this.executor = newSingleThreadScheduledExecutor(maxPriority(groupedThreads("OnosCopycat", "client", log)));
     }
 
     @Override
@@ -78,7 +79,7 @@
             return Tools.exceptionalFuture(new StorageException.Unavailable());
         }
         CompletableFuture<T> future = new CompletableFuture<>();
-        executor.submit(() -> submit(query, 1, future));
+        executor.execute(() -> submit(query, 1, future));
         return future;
     }