mod_netconf: BUGFIX deadlock on unknown session disconnect

Unlock mutex
diff --git a/src/mod_netconf.c b/src/mod_netconf.c
index c9434f5..d1e4394 100644
--- a/src/mod_netconf.c
+++ b/src/mod_netconf.c
@@ -308,6 +308,10 @@
 
 		return (EXIT_SUCCESS);
 	} else {
+		if (pthread_rwlock_unlock (&session_lock) != 0) {
+			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
+			return EXIT_FAILURE;
+		}
 		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Unknown session to close");
 		return (EXIT_FAILURE);
 	}