Revert UIDGenerator commits.

Revert UIDGenerator commits.

Changes seemed to be merged without anyone really looking at it
and the authorship in git is wrong as well. All related changes
can later be batched as one commit.

Following commit / change are reverted:

 - 7ac3edd https://gerrit.wikimedia.org/r/36803
 - 036d03b https://gerrit.wikimedia.org/r/36813
 - 2b168e3 https://gerrit.wikimedia.org/r/36812
 - 6030d92 https://gerrit.wikimedia.org/r/36801

See wikitech-l thread
http://lists.wikimedia.org/pipermail/wikitech-l/2012-December/064801.html

Change-Id: Ie39fde2ee4121372b6d790943f306e56fbacc2b5