Fix has_valid_cookie check.
Fix has_valid_cookie check.

Last night, when I was fixing bug 762, I was working from an ancient change on
reviewboard, and missed a "self". This change fixes it.

haosdent/rbtools,datjwu/rbtools,Khan/rbtools,clach04/old_rbtools_0.3.2,haosdent/rbtools,haosdent/rbtools,beol/rbtools,datjwu/rbtools,davidt/rbtools,beol/rbtools,Khan/rbtools,reviewboard/rbtools,davidt/rbtools,clach04/rbtools,halvorlu/rbtools,reviewboard/rbtools,beol/rbtools,bcelary/rbtools,1tush/rbtools,davidt/rbtools,reviewboard/rbtools,halvorlu/rbtools,halvorlu/rbtools,datjwu/rbtools,clach04/rbtools_0.4.1