[irods#858] Fix typo in heartbeat code comment.

server/main_server/src/agent_main.cpp

@@ -780,7 +780,7 @@ namespace
                     send(net_obj->socket_handle(), &(heartbeat[heartbeat_length - bytes_to_send]), bytes_to_send, 0);
 
                 // We do not check for 0 because it is not considered an error condition. It only means 0
-                // bytes were sent. As longs as we have more bytes to send and no error has occurred, we
+                // bytes were sent. As long as we have more bytes to send and no error has occurred, we
                 // keep attempting to send bytes.
                 if (bytes_sent == -1) {
                     const int errsav = errno;