pacstrap: remove obsolete option '-d' completely

This has been obsolete for 4 years and I can hardly imagine people still using it (only to find that it doesn't actually work).

pacstrap.in

@@ -47,14 +47,11 @@ if [[ -z $1 || $1 = @(-h|--help) ]]; then
   exit $(( $# ? 0 : 1 ))
 fi
 
-while getopts ':C:cdGiKMNU' flag; do
+while getopts ':C:cGiKMNU' flag; do
   case $flag in
     C)
       pacman_config=$OPTARG
       ;;
-    d)
-      # retired flag. does nothing.
-      ;;
     c)
       hostcache=1
       ;;