QFreeList: fix memory order on block deletion

Blocks are likely to have been created in a differnt thread from the one
performing their deletion, so we need an acquire fence.

The rest of the atomics use in the class looks ok, but nevertheless warrants
a deeper analysis.

Change-Id: I1571ded3a06695b0d58b5bf1d80d6283ac21f959
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 6fa34930c23c7494a3f2703777f46794ff091e2b)
(cherry picked from commit 51bcc7e07e2bb5b42bb200dcd5269e9e9e2fe240)
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

0 files changed, 0 insertions, 0 deletions