Backed out 5 changesets (bug 1049051) for B2G mochitest leaks.

Backed out changeset 4a283d42050c (bug 1049051)
Backed out changeset 06dd873bb3e9 (bug 1049051)
Backed out changeset 96b54c1771b6 (bug 1049051)
Backed out changeset f4fdedef6297 (bug 1049051)
Backed out changeset c4649e6ddd22 (bug 1049051)