Use LOfC-specific STARTCENTER_INFO_URL

Change-Id: I5a16033851fd1e8441d451f14295e0c8d664d001
For a sandboxed OS X LOfC, use a more specific URL

Change-Id: Ibe640c9557b987622a843d7e219f7fcd42f3b73a
Use LOfC-specific STARTCENTER_INFO_URL here, too

Change-Id: Ia7d5c8d28fec0e229edcdb8d23e381f21a266ae7
We probably don't offer localized pages on libreoffice-from-collabora.com

Change-Id: I207cecc3b4ff0ac5464137161eb02d51d9e39c5e