Properly return null if no readBinding is located when caching is active

Author: hugithordarson

ng-core/src/main/java/ng/kvc/NGKeyValueCoding.java

@@ -145,6 +145,11 @@ private static KVCReadBinding readBindingForKey( final Object object, final Stri
 
 			if( readBinding == null ) {
 				readBinding = locateBindingForKey( object, key );
+
+				if( readBinding == null ) {
+					return null;
+				}
+
 				_readBindingCache.put( cacheKey, readBinding );
 			}