Enable cyrus-sasl support by default

Testing Done:
Built and followed the sasl instructions on freenode's site https://freenode.net/kb/answer/pidgin and connected and identified me to nickserv just fine. Also I checked Debian and they're manually enabling this so if there was an issue users were seeing we would have heard about it by now as this line was last changed in 2013.

Reviewed at https://reviews.imfreedom.org/r/26/