update loxigen-artifacts

* submodules/loxigen-artifacts a75dc82...d8618ce (7):
  > Artifacts from https://github.com/floodlight/loxigen/compare/44aa60dc787d40fcd45b452e9c82505bf82251bf...1bfc0e32601b548d10261948f18220fd41144dd9
  > Artifacts from https://github.com/floodlight/loxigen/compare/314cb9fc6e9fc9316ee2c0bdbd2968d61102d173...44aa60dc787d40fcd45b452e9c82505bf82251bf
  > Artifacts from https://github.com/floodlight/loxigen/compare/10ef6eb7f14b1c6f6178ed832973d8d770a84811...314cb9fc6e9fc9316ee2c0bdbd2968d61102d173
  > Artifacts from https://github.com/floodlight/loxigen/compare/d34a44e7099812f84a5d913f669cf9a962cc8db3...10ef6eb7f14b1c6f6178ed832973d8d770a84811
  > Artifacts from https://github.com/floodlight/loxigen/compare/1567619f0e5d63f577c6afbaaf68a43e323f0a8c...d34a44e7099812f84a5d913f669cf9a962cc8db3
  > Artifacts from https://github.com/floodlight/loxigen/compare/83c7de7047d25904c531fc3a892ab87416f431aa...1567619f0e5d63f577c6afbaaf68a43e323f0a8c
  > Artifacts from https://github.com/floodlight/loxigen/compare/b34bd717880b534e70172081e5b5a94ee629dd43...83c7de7047d25904c531fc3a892ab87416f431aa
pipeline_lua: skeleton

Registers a new no-op "lua" pipeline.
pipeline_lua: create empty Lua state

We only support a single Lua state for now, so we need to lock it when
processing packets.
pipeline_lua: support uploading code
pipeline_lua: pass packet fields to lua
pipeline_lua: pass actx and stats pointers to Lua
pipeline_lua: support registering simple gentables from Lua
pipeline_lua: do per-packet global lookup in Lua code

This should be more efficient than hashing the string "ingress" for every
packet. The JIT can specialize lookups for a constant key.
Merge into master from pull request #214:
Experimental LuaJIT packet pipeline (https://github.com/floodlight/ivs/pull/214)