Bug 21612: Remove incorrect GROUP BY's from Koha::VirtualShelves

Bug 21612: Remove incorrect GROUP BY's from Koha::VirtualShelves

'koha_kohadev.me.shelfname' isn't in GROUP BY

Same as
  commit 7e220e0d8f107cce63f32bfaa1919c04b4dea6e2
  Bug 20179: [sql_modes] Remove GROUP BY in get_shelves_containing_record

Test plan:
- Add public and privates shelves
- Shares some of them
- List them
=> The correct numbers of shelves must be displayed

Signed-off-by: Andrew Isherwood <andrew.isherwood@ptfs-europe.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>