Bug 18756: Users can view aq.baskets even if they are not allowed

Bug 18756: Users can view aq.baskets even if they are not allowed

Due to bad use of grep syntax if there is one or more Basket Users the result of grep is not equal to 0 and the borrower is allowed.

Test plan :
1- select system preference 'AcqViewBaskets' on 'user'
2- create 2 borrowers (A, B) with only permissions on acquisition :
group_manage
order_manage
order_receive
staff
3- login with A and create a basket
4- add a basquet manager other than B
5- relog with account B
6- you can see the basket

Apply the patch.
The basket is no longer visible.
1- relog with A
2- add basquet manager B
3- relog with B
5- you must see the basket

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>