Fix gdbm for debian stable, configure problem with new howl

debian/changelog

@@ -1,4 +1,4 @@
-mt-daapd (0.2.0-pre1) unstable; urgency=low
+mt-daapd (0.2.0) unstable; urgency=low
   * Add gdbm database
   * Add support for .m4a and .m4p
   * Various bug fixes

debian/postinst

@@ -3,10 +3,12 @@
 action="$1"
 CONF=/etc/mt-daapd.conf
 PLAY=/etc/mt-daapd.playlist
+CACHE=/var/cache/mt-daapd
 
 case "$1" in
     configure)
         if [ ! -f $CONF ] ; then cp /usr/share/doc/mt-daapd/mt-daapd.conf $CONF; fi
         if [ ! -f $PLAY ] ; then cp /usr/share/doc/mt-daapd/mt-daapd.playlist $PLAY; fi
+	if [ ! -d $CACHE ] ; then mkdir -p $CACHE; fi
     ;;
 esac