Backed out 5 changesets (bug 894595) for causing new mochitest-bc intermittent failures.

Backed out changeset 778adbf10481 (bug 894595)
Backed out changeset 5b621d8eb5e9 (bug 894595)
Backed out changeset 91303ff403ac (bug 894595)
Backed out changeset 3caa785122bf (bug 894595)
Backed out changeset 108e2b8e177c (bug 894595)