Surround with a check since its not available in 1.2

Author: davidlgj

src/directives/array.js

@@ -130,7 +130,11 @@ angular.module('schemaForm').directive('sfArray', ['sfSelect', 'schemaForm', 'sf
             if (scope.validateArray) {
               scope.validateArray();
             }
-            ngModel.$setDirty();
+
+            // Angular 1.2 lacks setDirty
+            if (ngModel.$setDirty) {
+              ngModel.$setDirty();
+            }
             return list;
           };