BUG #12788: host / peer auth works after pg_ctl reload, then blocks server startup

The following bug has been logged on the website:

Bug reference:      12788
Logged by:          Daniel Howard
Email address:      dannyman@toldme.com
PostgreSQL version: 9.3.2
Operating system:   CentOS
Description:

Hello,

I naively added a line like this to pg_hba.conf:

host   all             postgres        x.x.x.x/32           peer

I ran pg_ctl reload.

I was then able to connect from x.x.x.x to do backups.

I then restarted the server, and it failed, with this error:

LOG:  peer authentication is only supported on local sockets

I removed the above line from pg_hba.conf and server completed startup.  I
can no longer connect from host x.x.x.x.

I can see why pg_ctl reload might gloss over a config issue instead of
bringing down the server, but that the invalid auth configuration then works
strokes me as a bug.

Thanks,
-danny