In python 3, all strings are considered as unicode string.
This patch drops the explicit unicode literal (u'...')
or (u"..") appearances from the unicode strings.
Note: The scope of the patch is to drop unicode literal prefix
from python source code files, documentation and comment are overlook.
Change-Id: I66389d3f4b236a50bd3f193d4e67c2ac10e6ca24