fix vars

src/mirrors.ipxe

@@ -3,9 +3,9 @@
 # Basic attempt at mirror rotation
 
 :mirror_start
-iseq mirror ${mirror_one} && set mirror ${mirror_two} && goto mirror_end ||
-iseq mirror ${mirror_two} && set mirror ${mirror_three} && goto mirror_end ||
-iseq mirror ${mirror_three} && set mirror ${mirror_one} && goto mirror_end || 
+iseq ${mirror} ${mirror_one} && set mirror ${mirror_two} && goto mirror_end ||
+iseq ${mirror} ${mirror_two} && set mirror ${mirror_three} && goto mirror_end ||
+iseq ${mirror} ${mirror_three} && set mirror ${mirror_one} && goto mirror_end || 
 echo Setting mirror to ${mirror}...
 
 :mirror_end