Revert "Fix an issue in DtlsIdentityStore when the store is destroyed before the worker thread task returns."

This reverts commit 93604daf0ea1fea1148ce07793bfa538d177c876.

TBR=pthatcher@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/40329004

Cr-Commit-Position: refs/heads/master@{#8704}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8704 4adac7df-926f-26a2-2b94-8c16560cd09d
4 files changed