Scap: purge mergeCdbFileUpdates symlink

Purge symlink to mergeCdbFileUpdates which was deleted from the scap
codebase in Ie967901.

Change-Id: Ia4b532a05e2f303e1e6f598279123d9c56e66294
Scap: Remove mergeCdbFileUpdates symlink

Remove mention of the deleted mergeCdbFileUpdates symlink entirely from
the manifest. This should not be merged until Ia4b532a has been merged
and applied on all effected hosts.

Change-Id: I38e53e0d850ccbdb0b85418c6406693d2b4d2293