Fix django-pipeline requirement url

* Add "git+" to start of django-pipeline url.  Fixes dev install on my system.

requirements.txt

@@ -13,7 +13,7 @@ python-memcached
 django-celery
 path.py
 django_debug_toolbar
--e git://github.com/MITx/django-pipeline.git@incremental_compile#egg=django-pipeline
+-e git+git://github.com/MITx/django-pipeline.git@incremental_compile#egg=django-pipeline
 django-staticfiles>=1.2.1
 django-masquerade
 fs