server: don't close log file fd on channel close

Channel can be reopened and log file fd won't be valid anymore. Also
emit error if error happened on channel.

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>
return ok by default from generated methods

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>
server: return rpc_error if module not found

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>
server: load autogenerated modules

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>