Improve fix bug #68421 access.format='%R' doesn't log ipv6 address

Log IPv4-Mapped-Ipv6 address as IPv4 (not as IPv6)
comment about ipv4-mapped in fpm conf
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  comment about ipv4-mapped in fpm conf
  Improve fix bug #68421 access.format='%R' doesn't log ipv6 address