Bug 21907: Fix article requests count for non-superlibrarians

Bug 21907: Fix article requests count for non-superlibrarians

The query generates "Column 'branchcode' in where clause is ambiguous"

Test plan:
1 - Enable 'IndependentBranchesPatronModifications' and article requests
2 - Sign in as non-superlibrarian
3 - View plack log
4 - Refresh mainpage, see error in logs

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>