repeated reloads lead to unresponsive server

[james.anderson]

we found it to be impractical to move from ubuntu's released nginx version
in order to avoid that the perl module crashed on _every_ reload.
i was unaware, that the presence of the nchan module could cause an issue if
one did not use it, but will disable it an see if that helps.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,289247,289252#msg-289252