add quotes to handle pathnames with spaces in it

Summary:
fixes #3135
Closes https://github.com/facebook/react-native/pull/4369

Reviewed By: svcscm

Differential Revision: D2752708

Pulled By: androidtrunkagent

fb-gh-sync-id: ada11eecb6bd5b8519e30636d18aa6b8962198aa

React/React.xcodeproj/project.pbxproj

@@ -608,7 +608,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "if nc -w 5 -z localhost 8081 ; then\n  if ! curl -s \"http://localhost:8081/status\" | grep -q \"packager-status:running\" ; then\n    echo \"Port 8081 already in use, packager is either not running or not running correctly\"\n    exit 2\n  fi\nelse\n  open $SRCROOT/../packager/launchPackager.command || echo \"Can't start packager automatically\"\nfi";
+			shellScript = "if nc -w 5 -z localhost 8081 ; then\n  if ! curl -s \"http://localhost:8081/status\" | grep -q \"packager-status:running\" ; then\n    echo \"Port 8081 already in use, packager is either not running or not running correctly\"\n    exit 2\n  fi\nelse\n  open \"$SRCROOT/../packager/launchPackager.command\" || echo \"Can't start packager automatically\"\nfi";
 		};
 		142C4F7F1B582EA6001F0B58 /* ShellScript */ = {
 			isa = PBXShellScriptBuildPhase;