Removed fallback check on each defineSecureProp call

This check was originally added because IE8's implementation is broken.
However, we already perform a test in the `can_define_prop` configuration,
so this is not necessary (it seems to be a relic).

lib/util.js

@@ -562,8 +562,8 @@ exports.defineSecureProp( exports.getPropertyDescriptor, 'canTraverse',
 
 
 /**
- * Appropriately returns defineSecureProp implementation to avoid check on each
- * invocation
+ * Appropriately returns defineSecureProp implementation to avoid check on
+ * each invocation
  *
  * @return  {function( Object, string, * )}
  */
@@ -584,26 +584,14 @@ function getDefineSecureProp()
         // uses ECMAScript 5's Object.defineProperty() method
         return function( obj, prop, value )
         {
-            try
+            Object.defineProperty( obj, prop,
             {
-                Object.defineProperty( obj, prop,
-                {
-                    value: value,
+                value: value,
 
-                    enumerable:   false,
-                    writable:     false,
-                    configurable: false,
-                });
-            }
-            catch ( e )
-            {
-                // let's not have this happen again, as repeatedly throwing
-                // exceptions will do nothing but slow down the system
-                exports.definePropertyFallback( true );
-
-                // there's an error (ehem, IE8); fall back
-                fallback( obj, prop, value );
-            }
+                enumerable:   false,
+                writable:     false,
+                configurable: false,
+            } );
         };
     }
 }