requirements_style_check.sh does not sort correctly on Mac

[andersonvom]

The sort command on Mac doesn't seem to have the same default sorting options that the Linux one does, so when checking the style of requirements.txt, it will output the incorrect sorting and fail the tests. The Linux sort takes only alphanumeric characters into account, thus not having this problem.

E.g.:

*** 26,27 ****
- SQLAlchemy>=0.7.8,<=0.9.99
  sqlalchemy-migrate>=0.9.1
--- 26,27 ----
  sqlalchemy-migrate>=0.9.1
+ SQLAlchemy>=0.7.8,<=0.9.99

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/96772

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/96772
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=797dcc8dc19c8bf74252a6713efd2c87e7591bc9
Submitter: Jenkins
Branch: master

commit 797dcc8dc19c8bf74252a6713efd2c87e7591bc9
Author: Anderson Mesquita <email address hidden>
Date: Fri May 30 10:01:59 2014 -0400

    Fix requirements_style_check on BSD platforms

    On Linux, the sort command implicitly ignore non-alphanumeric characters
    when sorting. Since the '>' character has an ASCII value greater than
    the '-' character, the following list will be sorted on Linux, but not
    on a Mac:

    SQLAlchemy>=0.7.8,<=0.9.99
    sqlalchemy-migrate>=0.9.1

    This makes sort explicitly ignore such characters and will keep the
    tests consistent across different environments.

    Closes-Bug: #1324945
    Change-Id: I559ae4b4c3e2a7d190af9d4b1517dfaf23d114b1