Unmute when we get a dtmfup (we muted on dtmfdown) event.

This would occasionally cause one-way audio when using hardware DTMF detection.

(closes issue #14761)
Reported by: tzafrir
Patches:
      v1-14761.patch uploaded by dimas (license 88)
Tested by: tzafrir, dimas


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@203258 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_dahdi.c

@@ -6965,6 +6965,7 @@ static struct ast_frame *dahdi_handle_event(struct ast_channel *ast)
 			/* absorb event */
 		} else {
 #endif
+			dahdi_confmute(p, 0);
 			p->subs[idx].f.frametype = AST_FRAME_DTMF_END;
 			p->subs[idx].f.subclass = res & 0xff;
 #ifdef HAVE_PRI