hurd: Support for file record locking

  [ Svante Signell ]
  * patches/hurd-i386/git-rlock.diff: New patch to add support for record
    locking.

  [ Samuel Thibault ]
  * patches/hurd-i386/tg-locarchive.diff,tg-WRLCK-upgrade.diff: Remove, now
    useless.
  * control: Bump hurd-dev dependency to get record locking RPC.
  * libc0.3.symbols.hurd-i386: Update accordingly.