fix watch file

debian/watch

 # Find first non-rc tarball linked from kernel.org.
 # We need to DFSG-clean it, so use our own script instead of uupdate.
 version=3
-http://ftp.debian.org/debian/pool/main/l/linux/ linux_(\d(?:[^~]*|.*~(?!exp\d)[^~]*))\.dsc
+http://ftp.debian.org/debian/pool/main/l/linux/ linux_(\d(?:[^~]*|.*~(?!exp\d)[^~]*))\.xz