Include /rw in the package

On Fedora it was created in %post, but on Debian not. Unify it to simply
provide the directory as standard package content.

Makefile

@@ -181,6 +181,7 @@ install-common:
 
 	install -d $(DESTDIR)/var/run/qubes
 	install -d $(DESTDIR)/home_volatile/user
+	install -d $(DESTDIR)/rw
 
 install-deb:
 	mkdir -p $(DESTDIR)/etc/apt/sources.list.d

rpm_spec/core-vm.spec

@@ -387,6 +387,7 @@ rm -f %{name}-%{version}
 %dir /home_volatile
 %attr(700,user,user) /home_volatile/user
 %dir /mnt/removable
+%dir /rw
 
 %package sysvinit
 Summary:        Qubes unit files for SysV init style or upstart