Move _LUSH_VERSION global into luaopen_base alongside _VERSION

lua.c

@@ -834,8 +834,6 @@ static int pmain (lua_State *L) {
     lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
   }
   luai_openlibs(L);  /* open standard libraries */
-  lua_pushstring(L, LUSH_VERSION);
-  lua_setglobal(L, "_LUSH_VERSION");
   createargtable(L, argv, argc, script);  /* create table 'arg' */
   lua_gc(L, LUA_GCRESTART);  /* start GC... */
   lua_gc(L, LUA_GCGEN);  /* ...in generational mode */