Revert "fix ng:include issue introduced by a5eb3ed1"

This reverts commit 17ee0f031a.

this and a5eb3ed1 introduced scope leakage that can't be resolved
until we fix up scope relationships and eval propagation.
I'm reverting both this and a5eb3ed1 until we can properly address
the issue.

src/widgets.js

@@ -635,12 +635,7 @@ angularWidget('ng:include', function(element){
         if (src) {
           xhr('GET', src, function(code, response){
             element.html(response);
-            if (useScope) {
-              childScope = useScope;
-            } else {
-              childScope = createScope(scope);
-              scope.$onEval(childScope.$eval);
-            }
+            childScope = useScope || createScope(scope);
             compiler.compile(element)(element, childScope);
             childScope.$init();
             scope.$eval(onloadExp);