Revert "Allow deleting instances while uuid lock is held"

This reverts commit 05f4f7170ab67c20e7f7b3f9f304ccc7ca163490.

We're seeing a huge increase in the occurrence of bug 1258848 since
this patch merged.  This patch effectively allows a delete to occur,
even if the creation hasn't finished yet, which would explain the race
we're seeing leading to the new flood of these errors.

Related-bug: #1258848
Change-Id: I6e44ac788426ba41f1674a5df3d04300eb7c05cc
Merge "Revert "Allow deleting instances while uuid lock is held""