Then that is something that is different with respect to CentOS 6.6, because the default.conf was just dropped when I re-installed it from the Nginx yum repository.

-rw-r--r--. root root system_u:object_r:httpd_config_t:s0 default.conf
-rw-r--r--. root root unconfined_u:object_r:httpd_config_t:s0 default.conf.orig

The default.conf above was dropped by a fresh install of the nginx package. The default.conf.orig was from my previous installation, where I renamed default.conf to default.conf.orig.

I definitely don't want to disable SELinux, as these are Internet facing servers.

Perhaps my next step should be to compile Nginx from source and see if it results in the same errors.