external: removes random123

Author: quesnel

.gitmodules

@@ -13,6 +13,3 @@
 [submodule "external/rapidjson"]
 	path = external/rapidjson
 	url = https://github.com/Tencent/rapidjson.git
-[submodule "external/random123"]
-	path = external/random123
-	url = https://github.com/DEShawResearch/random123.git

CMakeLists.txt

@@ -18,7 +18,6 @@ include_directories(${CMAKE_SOURCE_DIR}/external/leaf/include)
 include_directories(${CMAKE_SOURCE_DIR}/external/fmt/include)
 include_directories(${CMAKE_SOURCE_DIR}/external/ut/include)
 include_directories(${CMAKE_SOURCE_DIR}/external/rapidjson/include)
-include_directories(${CMAKE_SOURCE_DIR}/external/random123/include)
 
 file(COPY examples/
   DESTINATION