Backed out 4 changesets (bug 672843) for xpcshell bustage

Backed out changeset bbb7760083ae (bug 672843)
Backed out changeset eaf2fd75d7fc (bug 672843)
Backed out changeset eb08cc206b8d (bug 672843)
Backed out changeset 6a0e4afd52ab (bug 672843)