config: determine Suricata from suricata --build-info
Currently Suricata-Update will load the Python module
defaults that Suricata will write out during install. This is flawed as the user may specify an alternate Suricata and it doesn't know how to load the
defaults module from that other installation. Additionally, I hope to get rid of Python in Suricata-proper at some point in which case the defaults module won't exist.
For the first reason I am targetting this for 1.3.1.