#1364 Regression: Cannot add a second ECA to an entity

[John Locke]

Steps to reproduce:

1. Search for an existing Customer entity (Contacts -> Search)
2. Go to "Credit Account" tab
3. Clear "Number" field, change "Pay To", and click "Save New"

Result: existing credit account gets updated Pay To value and new Number.

Expected result: New credit count gets added to entity with new number and no other contact info.

[Anonymous]

Fix committed to 1.4.12.