[SMALLFIX] Fix logging message in ManagerProcessContext.java

### What changes are proposed in this pull request?

Fix logging messages in
hub/server/src/main/java/alluxio/hub/manager/process/ManagerProcessContext.java

### Why are the changes needed?

Fix #634 Alluxio/Community#634


### Does this PR introduce any user facing changes?

None

pr-link: #15068
change-id: cid-d8cda1723870cea7a8411055d781350ebe528878

hub/server/src/main/java/alluxio/hub/manager/process/ManagerProcessContext.java

@@ -398,7 +398,7 @@ private HostedManagerServiceGrpc.HostedManagerServiceStub getHostedAsyncStub() {
         mHostedAsyncSub =
                 HostedManagerServiceGrpc.newStub(channel);
       } catch (AlluxioStatusException e) {
-        LOG.error("Error connecting to hosted hub {}", e);
+        LOG.error("Error connecting to hosted hub: ", e);
       }
     }
     return mHostedAsyncSub;