git-svn fetch shows merge-base help

Hi,

sometimes when I do git-svn fetch I get following:

usage: git merge-base [-a|--all] <commit> <commit>...
   or: git merge-base [-a|--all] --octopus <commit>...
   or: git merge-base --independent <commit>...

    -a, --all             output all common ancestors
    --octopus             find ancestors for a single n-way merge
    --independent         list revs not reachable from others

W: Cannot find common ancestor between  and
e928383b6c16ef5a562f8c6f29d5568330c6b307. Ignoring merge info.
usage: git merge-base [-a|--all] <commit> <commit>...
   or: git merge-base [-a|--all] --octopus <commit>...
   or: git merge-base --independent <commit>...

    -a, --all             output all common ancestors
    --octopus             find ancestors for a single n-way merge
    --independent         list revs not reachable from others

W: Cannot find common ancestor between  and
6112c8ea3e8352d8c7511064faf013116e8a383e. Ignoring merge info.

[repeated several times]

r228807 = c70f12894de2e3278a8cf534f565cbf11533c170 (refs/remotes/tags/<TAG_NAME>)

$ git --version git version 1.7.11.1.104.ge7b44f1