Removing unnecessary comments

There is a change (I24f6e20cc8e310ba69fb23510795e235218abb2d) that
removes code lines with direct calls to fixtures cleanUp() to fix
bug #1469825. But in this patch we forgot to remove some comments
related to removed code lines. So this patch is intended to remove
such comments. 

Change-Id: I693ae1dec027a9ea6752314f3f95c5b042dc6f95
diff --git a/tempest/tests/common/test_accounts.py b/tempest/tests/common/test_accounts.py
index f2e8b20..2ca20f9 100644
--- a/tempest/tests/common/test_accounts.py
+++ b/tempest/tests/common/test_accounts.py
@@ -291,7 +291,6 @@
             {'username': 'test_user14', 'tenant_name': 'test_tenant14',
              'password': 'p', 'roles': ['role-7', 'role-11'],
              'resources': {'network': 'network-2'}}]
-        # Clear previous mock using self.test_accounts
         self.useFixture(mockpatch.Patch(
             'tempest.common.accounts.read_accounts_yaml',
             return_value=test_accounts))