Move 1.8.1pre2 symlink to proper directory

It needs to be in release/ and not at the repo root.

Change-Id: I493d8f0088e3860681b168f3baf633aae7d9e5ba
Reviewed-on: https://gerrit.openafs.org/13244
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: Benjamin Kaduk <kaduk@mit.edu>

diff --git a/openafs-1.8.1pre2.html b/release/openafs-1.8.1pre2.html
similarity index 100%
rename from openafs-1.8.1pre2.html
rename to release/openafs-1.8.1pre2.html