ChanIsAvail() generates a CDR when unanswered=yes in cdr.conf.

ChanIsAvail() creates a temporary channel with ast_request() to test
resource availability. It should not generate a CDR when it hangs up
this temporary channel.

This patch disables CDR generation for the temporary channel with
ast_cdr_set_property().

ASTERISK-28527

Change-Id: I7b0555c6909c7d322e452dde97c9ea5b111552d1

apps/app_chanisavail.c

@@ -178,6 +178,9 @@ static int chanavail_exec(struct ast_channel *chan, const char *data)
 					snprintf(tmp, sizeof(tmp), "%d", status);
 					ast_str_append(&tmp_availcause, 0, "%s%s", ast_str_strlen(tmp_availcause) ? "&" : "", tmp);
 
+					/* Disable CDR for this temporary channel. */
+					ast_cdr_set_property(ast_channel_name(tempchan), AST_CDR_FLAG_DISABLE_ALL);
+
 					ast_hangup(tempchan);
 					tempchan = NULL;