Validate scores before matching results in label queries

When searching for approvals we now double check that the user
who applied it to a patch set can still use the value stored.
If the permissions have changed, we retest based on the updated
permissions, potentially skipping the match.

Change-Id: Ia90c42405f6478a62c519b9fe80171c242b26984
Signed-off-by: Shawn O. Pearce <sop@google.com>
8 files changed