Bug 28956: Correct default tax rate on orderreceive

Bug 28956: Correct default tax rate on orderreceive

When there is more than one tax rate defined in system preferences, and
a vendor has a tax rate that is not 0%, then when you are receiving an
order in a basket for that vendor, the default tax rate should be the
correct non 0 rate. This should be seen in acqui/orderreceive.

To test:
1) Go to staff client
2) Go to Koha administration
3) Search for "tax rate" in system preferences
4) Add 0|0.15 into the preference
5) Create a vendor
6) Set vendor tax rate to 15%
7) Add a new basket to vendor
8) Add to basket
9) Add any sample order to basket - add actual cost
10) Close basket
11) Receive shipment
12) Make invoice
13) Click on Receive in the table
14) Should be on orderreceive.pl page
15) Observe tax rate default is 0%
16) Apply patch
17) Refresh page
18) Observe tax rate default is 15%

Sponsored-by: Catalyst IT
Signed-off-by: Julien Sicot <julien.sicot@univ-rennes2.fr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>