Merge branch 'mg/verify-commit'

Add 'verify-commit' to be used in a way similar to 'verify-tag' is used. Further work on verifying the mergetags might be needed. * mg/verify-commit: t7510: test verify-commit t7510: exit for loop with test result verify-commit: scriptable commit signature verification gpg-interface: provide access to the payload gpg-interface: provide clear helper for struct signature_check