Another safeguard around MC-forbidden retries

Adds a force_cancel key to transaction results that we
can check up in the Confirm_CreditCard transaction

Always send an antimessage at the start of Confirm_CreditCard for
everything except orphans.

Change-Id: Iead30f3d3d6a9f5d25f14d14261b9129aae973c6
Merge "Another safeguard around MC-forbidden retries"