log start and end of Shutdown()
log start and end of Shutdown()

- could be helpful when debugging shutdown related problems

Rebased-by:   Warren Togami <1e209d446a411c40b7ed7468db08be2b926e7895@gmail.com>
Rebased-from: ced3c248168941fbbd42d5a3807657a88be6a54e

dobbscoin/dobbscoin-source,Earlz/dobbscoin-source,Earlz/dobbscoin-source,dobbscoin/dobbscoin-source,dobbscoin/dobbscoin-source,Earlz/dobbscoin-source,dobbscoin/dobbscoin-source,Earlz/dobbscoin-source,Earlz/dobbscoin-source,Earlz/dobbscoin-source,dobbscoin/dobbscoin-source,dobbscoin/dobbscoin-source