Encapsulated conn ets table use in ibrowse_lb

Moved all interactions with ets table tracking
connections to API functions on ibrowse_lb,
to reduce knowledge of ets table and its structure.

Also fixed "bug" where ceiling for pipelining
threshold was different than the set value for increment;
made them the same.

src/ibrowse_http_client.erl

@@ -1939,31 +1939,22 @@ to_lower([], Acc) ->
 shutting_down(#state{lb_ets_tid = undefined}) ->
     ok;
 shutting_down(#state{lb_ets_tid = Tid}) ->
-    catch ets:delete(Tid, self()).
+    ibrowse_lb:report_connection_down(Tid).
 
 inc_pipeline_counter(#state{is_closing = true} = State) ->
     State;
 inc_pipeline_counter(#state{lb_ets_tid = undefined} = State) ->
     State;
 inc_pipeline_counter(#state{lb_ets_tid = Tid} = State) ->
-    update_counter(Tid, self(), {2,1,99999,9999}),
+    ibrowse_lb:report_request_underway(Tid),
     State.
 
-update_counter(Tid, Key, Args) ->
-    ets:update_counter(Tid, Key, Args).
-
 dec_pipeline_counter(#state{is_closing = true} = State) ->
     State;
 dec_pipeline_counter(#state{lb_ets_tid = undefined} = State) ->
     State;
 dec_pipeline_counter(#state{lb_ets_tid = Tid} = State) ->
-    _ = try
-	    update_counter(Tid, self(), {2,-1,0,0}),
-	    update_counter(Tid, self(), {3,-1,0,0})
-	catch
-	    _:_ ->
-		ok
-	end,
+    ibrowse_lb:report_request_complete(Tid),
     State.
 
 flatten([H | _] = L) when is_integer(H) ->

src/ibrowse_lb.erl

@@ -14,7 +14,10 @@
 -export([
 	 start_link/1,
 	 spawn_connection/6,
-     stop/1
+     stop/1,
+     report_connection_down/1,
+     report_request_underway/1,
+     report_request_complete/1
 	]).
 
 %% gen_server callbacks
@@ -68,6 +71,16 @@ stop(Lb_pid) ->
             ok
     end.
 
+report_connection_down(Tid) ->
+    catch ets:delete(Tid, self()).
+
+report_request_underway(Tid) ->
+    catch ets:update_counter(Tid, self(), {2, 1, 9999, 9999}).
+
+report_request_complete(Tid) ->
+    catch ets:update_counter(Tid, self(), {2, -1, 0, 0}),
+    catch ets:update_counter(Tid, self(), {3, -1, 0, 0}).
+
 %%====================================================================
 %% Server functions
 %%====================================================================