Bug 22010: Check preferences for ebook integration

Bug 22010: Check preferences for ebook integration

To test:
1 - Enable OverDrive and RecordedBooks (you can put anything in the
        prefs)
2 - Search on the opac - verify you get results (or search error) on
first page of results'
3 - Go to second page of results - OD and RB are not searched
4 - Apply patch
5 - Verify nothing has changed

If you have valid credentials:
1 - Enable RB prefs
2 - Sign in with an account that has an email matching your registered
account for recordedbooks
3 - Confirm you RB account loads on opac-user.pl

Otherwise:
Read the patches, verify it all makes sense

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>