Revert "Refactor PinStorage#storePin to avoid dead lock when unl..."

Revert submission 1832880-pin-storage

Reason for revert: DroidMonitor: Potential culprit for Bug 202289263 - verifying through Forrest before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.
Reverted Changes:
Ia6d8fe10d:Refactor PinStorage#storePin to avoid dead lock wh...
Ib84e75e7d:Refactor PinStorage#storePin to avoid dead lock wh...

Change-Id: I8d2baa6d6fdc1a39f22b66d521200b7dbd43e0b4
Merged-In: I8d2baa6d6fdc1a39f22b66d521200b7dbd43e0b4