Fix creation of /var/lock.

This directory will be fixed on the first launch of the guest, so
it is better to create it right away.  It aids proper management
of package files.

Makefile

@@ -94,6 +94,7 @@ install:
 	$(MKDIR) -p $(RUNDIR)
 	$(MKDIR) -p $(APPLIANCE_DIRS)
 	$(LN) -s /run $(APPLIANCE_DIR)
+	$(LN) -s /run/lock $(APPLIANCE_DIR)
 
 .MAIN: clean