Allow oauth for github in case of account has 2fa (two factor authentication) enabled

[whimboo]

I tried to run bugsahoy locally but was not able to given that my account has 2fa enabled and the CGI script bails out:

192.168.123.3 - - [15/May/2014 15:03:00] "GET /cgi-bin/githubapi.cgi?url=repos%2Fmozilla%2Fnightlytt%2Fissues%3Flabels%3Dmentored HTTP/1.1" 200 -
192.168.123.3 - - [15/May/2014 15:03:01] CGI script exit status 0x100

Would be nice if we can get such support.