Make django-admin name configurable in packages

[ingenieroariel]

The problem is the following:

When you install Django like this: pip install Django, you get django-admin.py.
When you install Django like this: apt-get install python-django, you get django-admin.

This is a problem with the install script that should work both for the manual installation and the package one.

My suggestion is to use the geonode.binary command in the install.sh script, and to make geonode.binary support the two use cases.

[simod]

thanks @ingenieroariel this could help but I don't have time to test now.
https://github.com/simod/geonode/tree/install-use-geonode