snf-ci: Remove obsolete ci config file

Remove ci_squeeze.conf config file. We do not support
Debian Squeeze any more.
snf-ci: Add command line option for repo/branch

This patch adds two new command line options to snf-ci:

* --synnefo-repo: Allows the user to specify the Synnefo repository
* --synnefo-branch: Allows the user to specify the Synnefo branch