Revert "Implement an "Action in progress" error."

This reverts commit faf984cbb5e62980e025191450a02d30aae8e02d.

Multi-engine support is being re-designed to account for the use-case in
bug #1211276.

Fixes bug #1211276

Change-Id: Ief89dd6a9c5014752db8065037dd1dd03efe789e
Merge "Revert "Implement an "Action in progress" error.""