Bug 1236729 - Fix some console errors on production
Bug 1236729 - Fix some console errors on production

Turns out that the treeherder code currently tries to get a
pushlog href when revision is undefined sometimes. Gracefully
fail for that case, as we did before.

kapy2010/treeherder,kapy2010/treeherder,edmorley/treeherder,kapy2010/treeherder,wlach/treeherder,KWierso/treeherder,edmorley/treeherder,tojonmz/treeherder,kapy2010/treeherder,tojonmz/treeherder,wlach/treeherder,tojon/treeherder,tojonmz/treeherder,akhileshpillai/treeherder,akhileshpillai/treeherder,KWierso/treeherder,glenn124f/treeherder,glenn124f/treeherder,tojon/treeherder,edmorley/treeherder,tojonmz/treeherder,glenn124f/treeherder,tojonmz/treeherder,KWierso/treeherder,wlach/treeherder,akhileshpillai/treeherder,tojon/treeherder,glenn124f/treeherder,akhileshpillai/treeherder,wlach/treeherder,tojonmz/treeherder,wlach/treeherder,kapy2010/treeherder,glenn124f/treeherder,KWierso/treeherder,tojon/treeherder,edmorley/treeherder,akhileshpillai/treeherder,glenn124f/treeherder,wlach/treeherder,akhileshpillai/treeherder