Bug#807120: Deprecate mod_rpaf, transition to mod_remoteip

[Konstantin Pavlov <thresh@nginx.com>]

The problem with mod_remoteip is that it is currently (first reported in
2013 [1]) broken in a setup where apache 2.4 is used behind a reverse
proxy.  remoteip module changes the client IP address (%a) but does not
change the host name (%h or REMOTE_HOST passed to other modules,
resolved via HostNameLookups On/Double).

apache2 2.4.10-10+deb8u4 and libapache2-mod-rpaf=0.6-13 do not suffer
from that problem.

[1] https://bz.apache.org/bugzilla/show_bug.cgi?id=55348

-- 
Konstantin Pavlov