Add main/1 so rebar2 escriptize works

Change-Id: Ifc3a58d09fbf5b9f36595515f47223a45ef13ba1

src/osmo_dia2gsup.erl

@@ -5,6 +5,8 @@
 -include_lib("diameter/include/diameter_gen_base_rfc6733.hrl").
 %-include_lib("diameter_settings.hrl").
 
+-export([main/1]).
+
 % API
 -export([start_link/0]).
 -export([start/0, stop/0]).
@@ -54,6 +56,9 @@ start() ->
 stop() ->
 	gen_server:cast(?SERVER, stop).
 
+main(_Args) ->
+	start().
+
 %% ------------------------------------------------------------------
 %% gen_server Function Definitions
 %% ------------------------------------------------------------------