HHVM: set REMOTE_ADDR envvar
HHVM: set REMOTE_ADDR envvar

Workaround for an intermittent "unable to determine IP" error.
I confirmed that REMOTE_ADDR is properly set to the remote IP for genuine web
requests.

Change-Id: Ia1d0460c2c242a7beb93564c1372487f9490e35d

HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,stuartbman/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,wikimedia/mediawiki-vagrant,stuartbman/mediawiki-vagrant,stuartbman/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer,wikimedia/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,stuartbman/mediawiki-vagrant,stuartbman/mediawiki-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,HarriAlasi/wiki3dviewer,wikimedia/mediawiki-vagrant,HarriAlasi/wiki3dviewer,HarriAlasi/wiki3dviewer,wikimedia/mediawiki-vagrant,wikimedia/mediawiki-vagrant,HarriAlasi/wiki3dviewer