fix up maintainer release instructions

maintainer.txt

@@ -4,7 +4,7 @@ ensure unit tests pass
 git flow release start X.Y.Z
 bump __version__ in sshkey/__init__.py
 git add sshkey/__init__.py
-git ci -m 'bump version'
+git commit -m 'bump version'
 python setup.py sdist
 git flow release finish X.Y.Z
 git push origin master X.Y.Z