Only the last CI result can be treated as merged

CI may leave several comments for the same patch set. This can happen if
tests are restarted by recheck command. For merged patchsets only the very last
result can be treated as final.

Change-Id: I5a0200089795cc132c083d9683ca4a4f70e37d5f
Merge "Only the last CI result can be treated as merged"