ensure account code is not overwritten when none is supplied (bug #4743)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6168 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_disa.c

@@ -329,7 +329,9 @@ static int disa_exec(struct ast_channel *chan, void *data)
 		}
 		strncpy(chan->exten, exten, sizeof(chan->exten) - 1);
 		strncpy(chan->context, ourcontext, sizeof(chan->context) - 1);
-		strncpy(chan->accountcode, acctcode, sizeof(chan->accountcode) - 1);
+		if (!ast_strlen_zero(acctcode)) {
+			strncpy(chan->accountcode, acctcode, sizeof(chan->accountcode) - 1);
+		}
 		chan->priority = 0;
 		ast_cdr_reset(chan->cdr,AST_CDR_FLAG_POSTED);
 		LOCAL_USER_REMOVE(u);