hurd-i386 updates for 2.28

  * debian/patches/hurd-i386/git-gscope.diff: upstreamed.
  * debian/patches/hurd-i386/git-hurd-abilist.diff: Remove patch, now useless.
  * debian/patches/hurd-i386/git-pagesize.diff: upstreamed.
  * debian/patches/hurd-i386/git-timer_routines.diff: upstreamed.
  * debian/patches/hurd-i386/submitted-net.diff: rebased.
  * debian/patches/hurd-i386/tg-context_functions.diff: update.
  * debian/patches/hurd-i386/tg-hurdsig-SA_SIGINFO.diff: update.
  * debian/patches/hurd-i386/tg-sysvshm.diff: update.
  * debian/patches/hurd-i386/tg-verify.h.diff: remove, now useless.
  * debian/patches/hurd-i386/tg2.26-sched_param.diff: upstreamed.
  * debian/testsuite-xfail-debian.mk: Update.