Bug 713132 - (Av1) Make packager.pm missing file warnings fatal on Firefox. r=khuey

browser/installer/Makefile.in

@@ -48,6 +48,7 @@ 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 \