[TYPO3-core] Another issue with EM and TER mirrors

[Martin Kutschker]

Hi!

It seems that the mirror of Vine-Hosting is down. The checksum file is gone:

http://mirror-typo3.vinehosting.com/ter/extensions.md5

Now for the EM issue. In random mode EM does not try to use another mirror 
if the selected one is down/gone.

Masi