Remove tempest duplicate copy of skip_unless_attr

tempest.lib has decorator skip_unless_attr which has been moved
to tempest_lib and now it is already moved to tempest.lib

This commit removes the duplicate copy of this decorator from api/utils.py

Change-Id: Ibac298b661fee40d7c29779526f0037f8a5338ba
diff --git a/tempest/api/compute/servers/test_list_server_filters.py b/tempest/api/compute/servers/test_list_server_filters.py
index 0b33d66..c1fbb12 100644
--- a/tempest/api/compute/servers/test_list_server_filters.py
+++ b/tempest/api/compute/servers/test_list_server_filters.py
@@ -14,7 +14,6 @@
 #    under the License.
 
 from tempest.api.compute import base
-from tempest.api import utils
 from tempest.common import fixed_network
 from tempest.common.utils import data_utils
 from tempest.common import waiters
@@ -89,7 +88,7 @@
                                         wait_until='ACTIVE')
 
     @test.idempotent_id('05e8a8e7-9659-459a-989d-92c2f501f4ba')
-    @utils.skip_unless_attr('multiple_images', 'Only one image found')
+    @decorators.skip_unless_attr('multiple_images', 'Only one image found')
     def test_list_servers_filter_by_image(self):
         # Filter the list of servers by image
         params = {'image': self.image_ref}
@@ -174,7 +173,7 @@
                          len([x for x in servers['servers'] if 'id' in x]))
 
     @test.idempotent_id('b3304c3b-97df-46d2-8cd3-e2b6659724e7')
-    @utils.skip_unless_attr('multiple_images', 'Only one image found')
+    @decorators.skip_unless_attr('multiple_images', 'Only one image found')
     def test_list_servers_detailed_filter_by_image(self):
         # Filter the detailed list of servers by image
         params = {'image': self.image_ref}
diff --git a/tempest/api/utils.py b/tempest/api/utils.py
deleted file mode 100644
index 00c93b7..0000000
--- a/tempest/api/utils.py
+++ /dev/null
@@ -1,37 +0,0 @@
-# Copyright 2012 OpenStack Foundation
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-"""Common utilities used in testing."""
-
-from tempest import test
-
-
-class skip_unless_attr(object):
-    """Decorator that skips a test if a specified attr exists and is True."""
-    def __init__(self, attr, msg=None):
-        self.attr = attr
-        self.message = msg or ("Test case attribute %s not found "
-                               "or False") % attr
-
-    def __call__(self, func):
-        def _skipper(*args, **kw):
-            """Wrapped skipper function."""
-            testobj = args[0]
-            if not getattr(testobj, self.attr, False):
-                raise test.BaseTestCase.skipException(self.message)
-            func(*args, **kw)
-        _skipper.__name__ = func.__name__
-        _skipper.__doc__ = func.__doc__
-        return _skipper