Disable Python 2.6 matrix.
Disable Python 2.6 matrix.

There is some state issue with multiple matrices running the tests at
the same time. Need to update the tests to not conflict.

hackebrot/tweepy,edsu/tweepy,takeshineshiro/tweepy,arunxarun/tweepy,tsablic/tweepy,aganzha/tweepy,atomicjets/tweepy,kcompher/tweepy,LikeABird/tweepy,tweepy/tweepy,wjt/tweepy,zhenv5/tweepy,nickmalleson/tweepy,cogniteev/tweepy,svven/tweepy,awangga/tweepy,yared-bezum/tweepy,raymondethan/tweepy,Choko256/tweepy,IsaacHaze/tweepy,iamjakob/tweepy,robbiewoods05/tweepy,vishnugonela/tweepy,techieshark/tweepy,rudraksh125/tweepy,truekonrads/tweepy,tuxos/tweepy,vivek8943/tweepy,elijah513/tweepy,kylemanna/tweepy,thelostscientist/tweepy,bconnelly/tweepy,sa8/tweepy,kskk02/tweepy,nickmalleson/tweepy,obskyr/tweepy,conversocial/tweepy,damchilly/tweepy,vikasgorur/tweepy,nickmalleson/tweepy,nickmalleson/tweepy,sidewire/tweepy,aleczadikian/tweepy,srimanthd/tweepy