cmdserver: write early exception to 'e' channel in 'unix' mode...
cmdserver: write early exception to 'e' channel in 'unix' mode
In 'unix' mode, the server is typically detached from the console. Therefore
a client couldn't see the exception that occurred while instantiating the
server object.
This patch tries to catch the early error and send it to 'e' channel even if
the server isn't instantiated yet. This means the error may be sent before the
initial hello message. So it's up to the client implementation whether to
handle the early error message or error out as protocol violation.
The error handling code is also copied to chgserver.py. I'll factor out them
later if we manage to get chg passes the test suite.
