[2.x] Fixes "Incorrect header size"

[nunomaduro]

As of the time of writing, we have documented that customers should stop their Octane servers using the "octane:stop" command. However, it appears that some customers are sending a SIGTERM signal to the "octane:start" command, as reported in this GitHub issue: #713. Specifically, during local development, people often use the Control + C shortcut in their terminals.

Although behind the scenes, we do invoke the "octane:stop" command when a SIGTERM signal is sent to the StartRoadRunnerCommand, there is an issue with the fact that "octane:stop" does not wait for the underlying worker to stop completely. As a result, there is a possibility that the worker may attempt to communicate with the master process (like a regular Laravel response with sleep(5)) after the master process has been stopped by the StartRoadRunnerCommand.

When this situation occurs, a RelayException exception is thrown from a RoadRunner worker, indicating its failure to communicate with the master process. So, there are two approaches to address this issue:

1. The first option is presented in this pull request. It provides a quick fix that simply "ignores" this specific exception when it occurs, without making any other changes. We document that the "octane:stop" command should be used anyway.
2. The second option involves implementing a more extensive fix. This would require modifying the "octane:stop" command to block and wait for each underlying worker to stop before proceeding with further actions, among other necessary adjustments.