Bug 1138535 - generate precomplete before signing for OSX; r=ted a=RyanVM

On OSX, the precomplete file is part of the signed package, so it needs
to be created before we sign. This broke because Windows is different,
where we need to sign first so that the EME voucher is generated from
the signed package, and the EME voucher is part of the precomplete file.

toolkit/mozapps/installer/upload-files.mk

@@ -552,10 +552,9 @@ endif
 
 ifdef MOZ_SIGN_PREPARED_PACKAGE_CMD
 ifeq (Darwin, $(OS_ARCH))
-MAKE_PACKAGE    = cd ./$(PKG_DMG_SOURCE) && $(MOZ_SIGN_PREPARED_PACKAGE_CMD) $(MOZ_MACBUNDLE_NAME) \
-                  && cd $(PACKAGE_BASE_DIR) \
-                  && (cd $(STAGEPATH)$(MOZ_PKG_DIR)$(_RESPATH) && $(CREATE_PRECOMPLETE_CMD)) \
-                  && $(INNER_MAKE_PACKAGE)
+MAKE_PACKAGE    = (cd $(STAGEPATH)$(MOZ_PKG_DIR)$(_RESPATH) && $(CREATE_PRECOMPLETE_CMD)) \
+                  && cd ./$(PKG_DMG_SOURCE) && $(MOZ_SIGN_PREPARED_PACKAGE_CMD) $(MOZ_MACBUNDLE_NAME) \
+                  && cd $(PACKAGE_BASE_DIR) && $(INNER_MAKE_PACKAGE)
 else
 MAKE_PACKAGE    = $(MOZ_SIGN_PREPARED_PACKAGE_CMD) $(MOZ_PKG_DIR) \
                   && $(or $(call MAKE_SIGN_EME_VOUCHER,$(STAGEPATH)$(MOZ_PKG_DIR)),true) \