Bug 20861: Correct EDI permissions on EDI messsages

Bug 20861: Correct EDI permissions on EDI messsages

The permission for EDI is edi_manage, but 2 pages asked
for manage_edi, allowing users not to access those.

To test:
- Add edi_manage to your permissions
- Try to access the EDIFACT messages from the
  acq start page
- Verify it doesn't work
- Apply patch and try again
- You should be able to access the page now
- Try to access the other page directly (if you don't
  have EDI data):
  /cgi-bin/koha/acqui/edimsg.pl
- Verify you can access the page and don't get a
  permission error

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>