Add specific compile flag to avoid deprecation warning

Will see us through OTP 20 and 21.

rebar.config

@@ -1,4 +1,5 @@
 {erl_opts, [warnings_as_errors,
+	    {platform_define, "^2[0-1]{1}", fsm_deprecated},
             {platform_define, "^1[7-8]{1}", old_rand},
             {platform_define, "^R", old_rand},
             {platform_define, "^R", no_sync}]}.

src/leveled_cdb.erl

@@ -46,6 +46,17 @@
 -behaviour(gen_fsm).
 -include("include/leveled.hrl").
 
+
+-ifdef(fsm_deprecated).
+-compile({nowarn_deprecated_function, 
+            [{gen_fsm, start, 3},
+                {gen_fsm, sync_send_event, 3},
+                {gen_fsm, sync_send_event, 2},
+                {gen_fsm, send_event, 2},
+                {gen_fsm, sync_send_all_state_event, 3},
+                {gen_fsm, send_all_state_event, 2}]}).
+-endif.
+
 -export([init/1,
             handle_sync_event/4,
             handle_event/3,

src/leveled_sst.erl

@@ -62,6 +62,14 @@
 
 -behaviour(gen_fsm).
 
+-ifdef(fsm_deprecated).
+-compile({nowarn_deprecated_function, 
+            [{gen_fsm, start, 3},
+                {gen_fsm, sync_send_event, 3},
+                {gen_fsm, send_event, 2},
+                {gen_fsm, send_all_state_event, 2}]}).
+-endif.
+
 -include("include/leveled.hrl").
 
 -define(MAX_SLOTS, 256).