Shopify/active_merchant — pull request #703 by melari (2013-05-22 15:48:00+00:00)
Title: SagePay: Don't include customer_number unless it is numeric.

**Problem**
Sagepay recently changed their API such that requests fail if a non-numeric value is sent in the optional `customer_number` field.

**Changes**
- Don't include the field if a non-numeric value is passed in.

Review @odorcicd @jduff