Currently slower storagenodes can slow down deletion queue.
To make piece deletion faster reduce the maximum time spent in
either dialing or piece deletion requests.
With this change:
* dial timeout is 3s
* request timeout is 15s
* fail threshold is set to 10min
Similarly, we'll mark storage node as failed when the timeout occurs.
The timeout usually indicates that the storagenode is overwhelmed.
Garbage collection will ensure that the pieces get deleted eventually.
Change-Id: Iec5de699f5917905f5807140e2c3252088c6399b
edb8d656de