Fix issue causing attribute not loading with getList

As specified in issue magento#17759, CustomerRepository::getList() is
unexpectedly returning NULL, when CustomerRepository::get() is correctly
returning the value. Specifying the attribute as billing_company instead
of company removes the conflict.

Author: teganbold

app/code/Magento/Customer/Model/ResourceModel/CustomerRepository.php

@@ -365,7 +365,7 @@ public function getList(SearchCriteriaInterface $searchCriteria)
             ->joinAttribute('billing_telephone', 'customer_address/telephone', 'default_billing', null, 'left')
             ->joinAttribute('billing_region', 'customer_address/region', 'default_billing', null, 'left')
             ->joinAttribute('billing_country_id', 'customer_address/country_id', 'default_billing', null, 'left')
-            ->joinAttribute('company', 'customer_address/company', 'default_billing', null, 'left');
+            ->joinAttribute('billing_company', 'customer_address/company', 'default_billing', null, 'left');
 
         $this->collectionProcessor->process($searchCriteria, $collection);
 

app/code/Magento/Customer/Test/Unit/Model/ResourceModel/CustomerRepositoryTest.php

@@ -740,7 +740,7 @@ public function testGetList()
             ->willReturnSelf();
         $collection->expects($this->at(7))
             ->method('joinAttribute')
-            ->with('company', 'customer_address/company', 'default_billing', null, 'left')
+            ->with('billing_company', 'customer_address/company', 'default_billing', null, 'left')
             ->willReturnSelf();
         $this->collectionProcessorMock->expects($this->once())
             ->method('process')