Merge pull request #3961 from kchadha/fix-error-logging

Fix error logging when workspace fails to update 

src/containers/blocks.jsx

@@ -325,7 +325,9 @@ class Blocks extends React.Component {
             // incomplete. Throwing the error would keep things like setting the
             // correct editing target from happening which can interfere with
             // some blocks and processes in the vm.
-            error.message = `Workspace Update Error: ${error.message}`;
+            if (error.message) {
+                error.message = `Workspace Update Error: ${error.message}`;
+            }
             log.error(error);
         }
         this.workspace.addChangeListener(this.props.vm.blockListener);