MINOR: stats: shows proxy in a stopped state

Previous patch b5c0d65 ("MINOR: proxy: disabled takes a stopping and a
disabled state") allows us to set 2 states for a stopped or a disabled
proxy. With this patch we are now able to show the stats of all proxies
when the process is in a stopping states, not only when there is some
activity on a proxy.

This patch should fix issue #1307.
diff --git a/src/stats.c b/src/stats.c
index 71e81c7..b767ce5 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -3617,10 +3617,10 @@
 
 		px = appctx->ctx.stats.obj1;
 		/* Skip the global frontend proxies and non-networked ones.
-		 * Also skip disabled proxies unless they are still holding active sessions.
+		 * Also skip proxies that were disabled in the configuration
 		 * This change allows retrieving stats from "old" proxies after a reload.
 		 */
-		if ((!px->disabled || px->served > 0) && px->uuid > 0 &&
+		if (!(px->disabled & PR_DISABLED) && px->uuid > 0 &&
 		    (px->cap & (PR_CAP_FE | PR_CAP_BE)) && !(px->cap & PR_CAP_INT)) {
 			if (stats_dump_proxy_to_buffer(si, htx, px, uri) == 0)
 				return 0;