MAGETWO-36367: Fix Messages in Setup CLI Commands

 - Expected exception message updates.

Author: Fred Sung

dev/tests/integration/testsuite/Magento/User/Model/UserTest.php

@@ -296,9 +296,9 @@ public function testHasAssigned2Role()
 
     /**
      * @expectedException \Magento\Framework\Exception\LocalizedException
-     * @expectedExceptionMessage Please enter a user name.
-     * @expectedExceptionMessage Please enter a first name.
-     * @expectedExceptionMessage Please enter a last name.
+     * @expectedExceptionMessage User Name is a required field.
+     * @expectedExceptionMessage First Name is a required field.
+     * @expectedExceptionMessage Last Name is a required field.
      * @expectedExceptionMessage Please enter a valid email.
      * @expectedExceptionMessage Password is required field.
      * @magentoDbIsolation enabled