Fix the broken UT of huawei driver for py34/35

The cause of failing unit tests is a bug in huawei driver.
When huawei driver logins to backend, it reads username/password from
huawei configuration file. If the username/password are configured as
plain text, huawei driver'll encode them and overwrite the encoded text
to the configuration file.

The encoding logic code is like this:
  six.text_type(base64.b64encode("***"))

For py27, this code works fine. However, for py34, this text_type
converting adds some extra words to result unicode string, like
"b'***'"('***' is the actual encoded result string).
Once driver reads the username/password again, it'll get the incorrect
text and then fail while jsonutils.dumps.

All the failed unit tests tried to call login twice, and triggered the
error condition said above.

This patch is just a workaround, because those failed tests actually
no need to login twice, the redundant login calls are removed.

Another patch will be commited to fix the problem thoroughly in huawei
driver.  Bug https://launchpad.net/bugs/1612149 has been raised for
that work, and will also analyze what changed to trigger this issue
only recently.

Change-Id: Ia6bf7bbb9ffb9644085bbdf4f5576f09215a877f
Closes-Bug: #1612149

manila/tests/share/drivers/huawei/test_huawei_nas.py

@@ -2815,9 +2815,7 @@ class HuaweiShareDriverTestCase(test.TestCase):
         self.mock_object(db,
                          'share_type_get',
                          mock.Mock(return_value=share_type))
-        self.driver.plugin.configuration.manila_huawei_conf_file = (
+
-            self.fake_conf_file)
-        self.driver.plugin.helper.login()
         self.assertRaises(exception.InvalidInput,
                           self.driver.manage_existing,
                           share,
@@ -2831,9 +2829,7 @@ class HuaweiShareDriverTestCase(test.TestCase):
         self.mock_object(db,
                          'share_type_get',
                          mock.Mock(return_value=share_type))
-        self.driver.plugin.configuration.manila_huawei_conf_file = (
+
-            self.fake_conf_file)
-        self.driver.plugin.helper.login()
         self.assertRaises(exception.InvalidHost,
                           self.driver.manage_existing,
                           share,
@@ -3074,7 +3070,6 @@ class HuaweiShareDriverTestCase(test.TestCase):
         self.recreate_fake_conf_file(multi_url=True)
         self.driver.plugin.configuration.manila_huawei_conf_file = (
             self.fake_conf_file)
-        self.driver.plugin.helper.login()
         self.driver.plugin.helper.test_multi_url_flag = 2
         location = self.driver.create_share(self._context, self.share_nfs,
                                             self.share_server)
@@ -3084,7 +3079,6 @@ class HuaweiShareDriverTestCase(test.TestCase):
         self.recreate_fake_conf_file(multi_url=True)
         self.driver.plugin.configuration.manila_huawei_conf_file = (
             self.fake_conf_file)
-        self.driver.plugin.helper.login()
         self.driver.plugin.helper.test_multi_url_flag = 1
         self.assertRaises(exception.InvalidShare,
                           self.driver.create_share,
@@ -3716,7 +3710,6 @@ class HuaweiShareDriverTestCase(test.TestCase):
         backend_details = self.driver.setup_server(self.fake_network_info)
         fake_share_server = {'backend_details': backend_details}
 
-        self.driver.plugin.helper.login()
         location = self.driver.ensure_share(self._context,
                                             share,
                                             fake_share_server)