Fix that saving completed order would delete store credit adjustments
Fix that saving completed order would delete store credit adjustments

Because when the order is completed the credits are consumed, the
user no longer has sufficient credit to cover the adjustments so
they were being destroyed.

gogo52cn/spree_store_credits,developingchris/spree_store_credits,developingchris/spree_store_credits,spree-contrib/spree_store_credits,gogo52cn/spree_store_credits,gogo52cn/spree_store_credits,spree-contrib/spree_store_credits,dotandbo/spree_store_credits,migme/spree_store_credits,AgilTec/spree_store_credits,migme/spree_store_credits,developingchris/spree_store_credits,migme/spree_store_credits,dotandbo/spree_store_credits,AgilTec/spree_store_credits,AgilTec/spree_store_credits