Bug 26723: Improve link text on OverDriveAuthName system preference

Bug 26723: Improve link text on OverDriveAuthName system preference

The OverDriveAuthName system preference contains a link labeled "here"
to a seperate administration page that should be labeled better. This
patch renames the link.

To test:
1. Go to administration
2. Search the system preferences for OverDriveAuthName
3. Obeserve the "here" link in the preference.
4. Apply the patch.
5. Repeat steps 1-2.
6. Observe the new link text.
7. Sign off.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>