bitbake: rename REGEX, REGEX_URI, and GITTAGREGEX.
Rename REGEX to UPSTREAM_CHECK_REGEX, REGEX_URI to UPSTREAM_CHECK_URI, and
GITTAGREGEX to UPSTREAM_CHECK_GITTAGREGEX to better reflect their purpose
and to reflect a common namespace.
Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>