oe-build-perf-report: relax metadata matching rules

oe-build-perf-report: relax metadata matching rules

As the poky repository is no longer used, measurements are indexed using
the oe-core commit. But as bitbake, oe-core and meta-yocto are now
retrieved from separate gits, while measuring performances for a given branch
at some time interval, we can get the same commit for oe-core but
different ones for bitbake or meta-yocto. As a consequence, metadata
associated with the same index (oe-core commit) might differ.

To work around this, relax the equality checks for commit, commit_time
and commit_count since they might no longer match.

Ideally we'd group them into separate results but for now, treat them
as being the same.

[Based on work from Mathieu Dubois-Briand but fixed differently]
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>