make lua a rollable dep, roll it

This rolls from 5.2.1 (2013) to 5.3.4 (2017).

I was looking at why the GomaNoFallback bot was failing,
and noticed that we had a static copy of Lua here instead
of a DEPS entry.  This doesn't do anything to change the
GomaNoFallback situation.

Change-Id: Ia3cdca85551fe680b60b38cb8c5a8fb5349e177f
Reviewed-on: https://skia-review.googlesource.com/93120
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/DEPS b/DEPS
index 16fb60e..c15c5cf 100644
--- a/DEPS
+++ b/DEPS
@@ -15,6 +15,7 @@
   "third_party/externals/libjpeg-turbo" : "https://github.com/libjpeg-turbo/libjpeg-turbo.git@1.5.3",
   "third_party/externals/libpng"        : "https://skia.googlesource.com/third_party/libpng.git@v1.6.33",
   "third_party/externals/libwebp"       : "https://chromium.googlesource.com/webm/libwebp.git@v0.6.0",
+  "third_party/externals/lua"           : "https://github.com/lua/lua@v5-3-4",
   "third_party/externals/microhttpd"    : "https://android.googlesource.com/platform/external/libmicrohttpd@748945ec6f1c67b7efc934ab0808e1d32f2fb98d",
   "third_party/externals/piex"          : "https://android.googlesource.com/platform/external/piex.git@8f540f64b6c170a16fb7e6e52d61819705c1522a",
   "third_party/externals/sdl"           : "https://skia.googlesource.com/third_party/sdl@5d7cfcca344034aff9327f77fc181ae3754e7a90",