/sbin/login seems to not work for pull/push

Commit: 6286ada9 PR: https://github.com/gitlabhq/gitlab-recipes/pull/179

Reported issues:

• https://github.com/gitlabhq/gitlabhq/issues/6406
• https://github.com/gitlabhq/gitlab-recipes/issues/193
• https://github.com/gitlabhq/gitlab-recipes/pull/205
• https://groups.google.com/forum/#!topic/gitlabhq/Op4iqGllfcc

From man su

 -s, --shell=shell
   Runs the specified shell instead of the default.   The  shell  to
    run is selected according to the following rules, in order:

    o      the shell specified with --shell

    o      the  shell specified in the environment variable SHELL,
            if the --preserve-environment option is used

    o      the shell listed in the passwd entry of the target user

    o      /bin/sh

   If the target user has a restricted shell  (i.e.  not  listed  in
    /etc/shells),  the --shell option and the SHELL environment vari‐
    ables are ignored unless the calling user is root.

Possible solution: change git user shell to /bin/bash.