SONAR suggestion - proper handling of InterruptedException

Change-Id: I67a93c064708c207d9ce83fac319682c2d17db60
diff --git a/protocols/grpc/ctl/src/main/java/org/onosproject/grpc/ctl/GrpcControllerImpl.java b/protocols/grpc/ctl/src/main/java/org/onosproject/grpc/ctl/GrpcControllerImpl.java
index bbcd99f..6f233c8 100644
--- a/protocols/grpc/ctl/src/main/java/org/onosproject/grpc/ctl/GrpcControllerImpl.java
+++ b/protocols/grpc/ctl/src/main/java/org/onosproject/grpc/ctl/GrpcControllerImpl.java
@@ -171,6 +171,7 @@
             } catch (InterruptedException e) {
                 log.warn("Channel {} didn't shut down in time.");
                 channel.shutdownNow();
+                Thread.currentThread().interrupt();
             }
 
             channels.remove(channelId);