Rename pytest_plugins to ipatests.pytest_ipa

pytest 3.7.0 doesn't like ipatests.pytest_plugins package. The string
"pytest_plugins" is used as marker to load plugins. By populare vote and
to avoid future conflicts, we decided to rename the directory to pytest_ipa.

Fixes: https://pagure.io/freeipa/issue/7663
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

ipatests/test_integration/test_external_ca.py

@@ -22,7 +22,7 @@ import re
 import time
 import tempfile
 
-from ipatests.pytest_plugins.integration import tasks
+from ipatests.pytest_ipa.integration import tasks
 from ipatests.test_integration.base import IntegrationTest
 from ipaplatform.paths import paths