qemu_iotests: Remove _readlink()

It is unused.

Suggested-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>

tests/qemu-iotests/common.config

@@ -217,23 +217,5 @@ fi
 
 export SAMPLE_IMG_DIR
 
-_readlink()
-{
-    if [ $# -ne 1 ]; then
-        echo "Usage: _readlink filename" 1>&2
-        exit 1
-    fi
-
-    perl -e "\$in=\"$1\";" -e '
-    $lnk = readlink($in);
-    if ($lnk =~ m!^/.*!) {
-        print "$lnk\n";
-    }
-    else {
-        chomp($dir = `dirname $in`);
-        print "$dir/$lnk\n";
-    }'
-}
-
 # make sure this script returns success
 true