Back out a0fa92215a36 (bug 713132) for breaking --disable-updater as used in RPM nightlies

browser/installer/Makefile.in

@@ -48,7 +48,6 @@ include $(topsrcdir)/config/rules.mk
 MOZ_PKG_REMOVALS = $(srcdir)/removed-files.in
 
 MOZ_PKG_MANIFEST_P = $(srcdir)/package-manifest.in
-MOZ_PKG_FATAL_WARNINGS = 1
 
 MOZ_NONLOCALIZED_PKG_LIST = \
 	xpcom \