1009429 - Move pulp_manage_puppet bool 2 celery_t.

https://bugzilla.redhat.com/show_bug.cgi?id=1009429
Adds a plugin.misc helper function get_parent_directory with tests
Fixes a mistake in a unit test and removes an extra space in docs
Merge pull request #1192 from bmbouter/1149894

1149894 - Adds a get_parent_directory that gets it right with a trailing slash
PR review tweaks.
Merge branch '1009429' into 2.5-testing
Merge branch '2.5-testing' into 2.5-dev

Conflicts:
	server/pulp/plugins/util/misc.py
	server/test/unit/plugins/util/test_misc.py
Merge branch '2.5-dev'