I've heard many arguments for .05 being the highest acceptable for research but it seems like you have found an acceptable p-value that is out of that range by quite a bit.
I figure that if the test is at 90% confidence, it usually means we can't really make a really really bad decision going with the favorite. So what if that tiny increase in conversions wasn't really there, I figure its time to move on to another, possibly more lucrative test. Maybe Patrick has a different or more fleshed out opinion on this.