certcheck.py - small fixes
certcheck.py - small fixes

Change-Id: I4f13aafc4a388b8cd67a7a41e3f1bc3bbd3d66a7
Reviewed-on: https://gerrit.spotify.net/gerrit/72342
Reviewed-by: Paweł Rozlach <bb6340f668e0a0e9a9592e4f835bf23c6026f908@spotify.com>

spotify/certcheck