HDDS-786. Fix the findbugs for SCMClientProtocolServer#getContainerWithPipeline.

(cherry picked from commit 2e8ac14dcb57a0fe07b2119c26535c3541665b70)

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/server/SCMClientProtocolServer.java

@@ -188,7 +188,6 @@ public class SCMClientProtocolServer implements
         }
       }
     }
-    String remoteUser = getRpcRemoteUsername();
     getScm().checkAdminAccess(null);
     return scm.getContainerManager()
         .getContainerWithPipeline(containerID);