fix UIExplorer build path

Summary:
UIExplorerApp.ios.js is moved into js directory.
Closes https://github.com/facebook/react-native/pull/8884

Differential Revision: D3586032

Pulled By: nathanajah

fbshipit-source-id: 93793681e33a0922e3d8503da3f1c0d01fd4fa93

Examples/UIExplorer/UIExplorer.xcodeproj/project.pbxproj

@@ -902,7 +902,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "export NODE_BINARY=node\n$SRCROOT/../../packager/react-native-xcode.sh Examples/UIExplorer/UIExplorerApp.ios.js";
+			shellScript = "export NODE_BINARY=node\n$SRCROOT/../../packager/react-native-xcode.sh Examples/UIExplorer/js/UIExplorerApp.ios.js";
 		};
 /* End PBXShellScriptBuildPhase section */