Revert import from D4133936 (13aba8)

Summary:
This broke the open source build: http://imgur.com/a/1Btd1

javache tells me reverting this line should fix it.

Reviewed By: javache, ericvicenti

Differential Revision: D4178951

fbshipit-source-id: c680de6b3b48bf137294dfe053afaff7b0613caf

React/Executors/RCTJSCWrapper.h

@@ -9,7 +9,7 @@
 
 #import <JavaScriptCore/JavaScriptCore.h>
 
-#import <FBReactKit/RCTDefines.h>
+#import "RCTDefines.h"
 
 typedef void (*voidWithNoParamsFuncType)();
 typedef JSStringRef (*JSStringCreateWithCFStringFuncType)(CFStringRef);