fix library/utility lint warnings

Summary: I have disected lint warnings fixes to several PRs. This one fixes lint warnings under Libraries/Utility path.
Closes https://github.com/facebook/react-native/pull/4444

Reviewed By: svcscm

Differential Revision: D2705303

Pulled By: spicyj

fb-gh-sync-id: c745ac62cbff30d6bb9478a1d2465fe56b305f0c

Libraries/Utilities/MessageQueue.js

@@ -16,7 +16,6 @@
 let BridgeProfiling = require('BridgeProfiling');
 let ErrorUtils = require('ErrorUtils');
 let JSTimersExecution = require('JSTimersExecution');
-let ReactUpdates = require('ReactUpdates');
 
 let invariant = require('invariant');
 let keyMirror = require('keyMirror');

Libraries/Utilities/createStrictShapeTypeChecker.js

@@ -24,7 +24,7 @@ function createStrictShapeTypeChecker(
       if (isRequired) {
         invariant(
           false,
-          `Required object \`${propName}\` was not specified in `+
+          `Required object \`${propName}\` was not specified in ` +
           `\`${componentName}\`.`
         );
       }