Slirp updates

Daniel P. Berrangé (1):
  configure: remove slirp submodule support that doesn't exist yet

Marc-André Lureau (1):
  slirp: remove empty state.h

# gpg: Signature made Wed 13 Mar 2019 21:18:35 GMT
# gpg:                using RSA key E61DBB15D4172BDEC97E92D9DB550E89F0FA54F3
# gpg: Good signature from "Samuel Thibault <samuel.thibault@aquilenet.fr>" [unknown]
# gpg:                 aka "Samuel Thibault <sthibault@debian.org>" [marginal]
# gpg:                 aka "Samuel Thibault <samuel.thibault@gnu.org>" [unknown]
# gpg:                 aka "Samuel Thibault <samuel.thibault@inria.fr>" [marginal]
# gpg:                 aka "Samuel Thibault <samuel.thibault@labri.fr>" [marginal]
# gpg:                 aka "Samuel Thibault <samuel.thibault@ens-lyon.org>" [marginal]
# gpg:                 aka "Samuel Thibault <samuel.thibault@u-bordeaux.fr>" [unknown]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 900C B024 B679 31D4 0F82  304B D017 8C76 7D06 9EE6
#      Subkey fingerprint: E61D BB15 D417 2BDE C97E  92D9 DB55 0E89 F0FA 54F3

* remotes/thibault/tags/samuel-thibault:
  configure: remove slirp submodule support that doesn't exist yet
  slirp: remove empty state.h

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>