Python 3 doesn't have basestring type as all string
are unicode strings.
(From OE-Core rev: e8cfab060f4ff3c4c16387871354d407910e87aa)
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>