check-path: when running manually triggers builds for random prs

[gbenhaim]

See the builds in http://jenkins.ovirt.org/job/lago-demo_master_github_check-patch-el7-x86_64/ from 11:30 am.

[nvgoldin]

Yep you must put master in the sha1, iirc not different than Lago's check-patch.

[gbenhaim]

will be fixed by https://gerrit.ovirt.org/#/c/84805/