Bug 1072159 - Emphasise treeherder URLs in Try emails & fix for try-comm-central; r=nthomas

* Emphasise treeherder over TBPL, since the treeherder transition is imminent.
* s/thunderbird-try/try-comm-central/ for treeherder, now that it uses the
  hg/buildbot name (bug 1035222).
* Remove unused import and fix flake8 whitespace warning.
Merging from default

changeset:   3876:075057c36097
tag:         tip
parent:      3867:758fc60063ac
user:        Ed Morley <emorley@mozilla.com>
date:        Wed Sep 24 12:56:56 2014 +0100
summary:     Bug 1072159 - Emphasise treeherder URLs in Try emails & fix for try-comm-central; r=nthomas

--HG--
branch : production-0.8