packages: Adding more supported Linux Distribution

This commit add much more linux distribution to be used with DIST=
variable.

Debian : squeeze|wheezy|jessie
Ubuntu : lucid|precise|quantal|raring|saucy|trusty
Redhat : redhat
Centos : centos

In addition, the "distributions" file own the whole definition and makes
it available for the other files. This will avoid multiple
copy/paste/definition of the supported distro.

We had multiple wheezy or precise strings definition while a single
variable can own all of them.