oeqa/utils/gitarchive: replace warning with info when reading local tags

oeqa/utils/gitarchive: replace warning with info when reading local tags

Whenever a script needs to list tags, if it falls back to the third method
(reading local tags only), it emits a warning. While this warning is useful
for future diagnostic if some tagging issues re-appear, it makes buildperf
autobuilds status as "Passed with warnings", which is not desirable

Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>