fix undefined in info message

when no changes had been made
New release tag humpub-release-72-02

Generated by /nfs/users/nfs_m/mca/gitwk-anacode/team_tools.stable/otterlace/release/scripts/otterlace_release_tag (otter/68-53-g94b375d from intcvs1:/repos/git/anacode/team_tools.git)
bug fix fix
New release tag humpub-release-72-03

Generated by /nfs/users/nfs_m/mca/gitwk-anacode/team_tools.stable/otterlace/release/scripts/otterlace_release_tag (otter/68-53-g94b375d from intcvs1:/repos/git/anacode/team_tools.git)