return non-zero value when unsuccessfully exiting

[alxndr]

bash treats a zero return value as a success. gitc still returns zero if it encounters an error during an operation.

11:01:57 (rc-12350-backbonize-mediajs)
~/workspace/br/breport $ gitc pull

Retrieving branch information from gitcycle.

Fetching remote 'br'.


Merging remote branch 'rc' from 'br/breport'.

error: Your local changes to the following files would be overwritten by merge:
    public/javascripts/backbone/views/media_video_view.js
Please, commit your changes or stash them before you can merge.
Aborting


Gitcycle encountered an error when running the last command:
  git merge br/rc
Please copy this session's output and send it to gitcycle@bleacherreport.com.


11:02:04 (rc-12350-backbonize-mediajs)
~/workspace/br/breport $ echo $?
0

This means that chaining commands like gitc pull && bundle doesn't end up doing what you'd expect.