Fix ConfBridge crash if no timing module loaded.

(closes issue ASTERISK-19448)
Reported by: feyfre
Patches:
      smfix.patch (license #6099) patch uploaded by feyfre
      Modified for coding guidelines.
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Merged revisions 375496 from http://svn.asterisk.org/svn/asterisk/branches/10
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Merged revisions 375506 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@375511 65c4cc65-6c06-0410-ace0-fbb531ad65f3

bridges/bridge_softmix.c

@@ -297,7 +297,10 @@ static void softmix_translate_helper_cleanup(struct softmix_translate_helper *tr
 static void softmix_bridge_data_destroy(void *obj)
 {
 	struct softmix_bridge_data *softmix_data = obj;
-	ast_timer_close(softmix_data->timer);
+
+	if (softmix_data->timer) {
+		ast_timer_close(softmix_data->timer);
+	}
 }
 
 /*! \brief Function called when a bridge is created */