Handle only LockNotGrantedException for heartbeat

If we don't have a connection to AWS or our thread is interrupted
for some reason, we should just re-throw that exception as is.

* Only catch a `LockNotGrantedException` which really indicates
that the state of the lock record has been changed.
Therefore we also have to reset local state and try again

Author: artembilan

src/main/java/org/springframework/integration/aws/lock/DynamoDbLockRegistry.java

@@ -56,6 +56,7 @@
 import com.amazonaws.services.dynamodbv2.model.CreateTableRequest;
 import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
 import com.amazonaws.services.dynamodbv2.model.KeyType;
+import com.amazonaws.services.dynamodbv2.model.LockNotGrantedException;
 import com.amazonaws.services.dynamodbv2.model.LockTableDoesNotExistException;
 import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;
 import com.amazonaws.services.dynamodbv2.model.ResourceInUseException;
@@ -532,7 +533,7 @@ private boolean doLock() throws InterruptedException {
 					this.lockItem.sendHeartBeat();
 					acquired = true;
 				}
-				catch (Exception e) {
+				catch (LockNotGrantedException ex) {
 					// May be no lock record in the DB - discard local holder and try to lock again
 					this.lockItem = null;
 				}