localize doc strings

A number of doc strings were not localized, wrap them in _().
Some messages were not localized, wrap them in _()

Fix a couple of failing tests:
The method name in RPC should not be unicode.
The doc attribute must use the .msg attribute for comparison.

Also clean up imports of _() The import should come from
ipalib or ipalib.text, not ugettext from request.

tests/util.py

@@ -31,8 +31,6 @@ import ipalib
 from ipalib.plugable import Plugin
 from ipalib.request import context
 
-
-
 class TempDir(object):
     def __init__(self):
         self.__path = tempfile.mkdtemp(prefix='ipa.tests.')