Back out dd103ec4c44b through fba3a342a530 because of B2G test failures on a CLOSED TREE

--HG--
rename : toolkit/system/gnome/nsSystemAlertsService.cpp => toolkit/system/gnome/nsAlertsService.cpp
rename : toolkit/system/gnome/nsSystemAlertsService.h => toolkit/system/gnome/nsAlertsService.h