[SAC] OSGeo 7 host updates

I'm going to be installing some updates on OSGeo 7 server and will require a
reboot of the host.

I don't expect more than 30 minutes - 1 hr downtime.
I'll notify once things are back to normal.

Services that will be impacted are listed on this page:

Given that wiki will be affected, I will repeat the most critical ones
ldap.osgeo.org (which pretty much affects everything)
osgeo.org, www.osgeo.org
download.osgeo.org, bottles.download.osgeo.org
trac.osgeo.org, git.osgeo.org, wiki.osgeo.org