Add support for get group only if exist in regex, this enables to use
this function in _check_latestversion regardless if the regex is generic
or specified by REGEX_URI.
(Bitbake rev: 1127af5b8c458929c4685b0326f86870ed09442e)
Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>