Merge branch 'jk/rev-input-given-fix'

Feeding "$ZERO_OID" to "git log --ignore-missing --stdin", and running "git log --ignore-missing $ZERO_OID" fell back to start digging from HEAD; it has been corrected to become a no-op, like "git log --tags=no-tag-matches-this-pattern" does. * jk/rev-input-given-fix: revision: set rev_input_given in handle_revision_arg()