Add missing check_conn when running SQL statements

Intermittent errors from the DB can cause the connection to be reset and
not re-established for the next statement to be executed, leading to
segfaults.

fixes #742

Change-Id: I1ed5b75457ab7167a70df5e04a964d37f98e60f7

recording-daemon/db.c

@@ -159,6 +159,8 @@ INLINE void my_d(MYSQL_BIND *b, const double *d) {
 static void execute_wrap(MYSQL_STMT **stmt, MYSQL_BIND *binds, unsigned long long *auto_id) {
 	int retr = 0;
 	while (1) {
+		if (check_conn())
+			goto err;
 		if (mysql_stmt_bind_param(*stmt, binds))
 			goto err;
 		if (mysql_stmt_execute(*stmt))