Devserver logs previous client versions.

This is a necessary functionality for automated testing of autoupdates.

BUG=chromium-os:25028
TEST=Autoupdating with devserver works, devserver records previous
client version after a successful update.

Change-Id: I1be484220447a4ccd39ee9e723e06f7f4cfe7a98
Reviewed-on: https://gerrit.chromium.org/gerrit/18055
Commit-Ready: Gilad Arnold <[email protected]>
Reviewed-by: Gilad Arnold <[email protected]>
Tested-by: Gilad Arnold <[email protected]>
1 file changed