Increase timeout period for clone volume.

Increase timeout period for clone volume.

Current timeout value for clone volume in the
SolidFire driver is 20 seconds, this is fine
in many cases however there seems to be a
number of customers doing clones of
volumes >= 400G.

A populated 400G volume is taking upwards of
35 seconds to clone in some cases resulting in failure.

There's no reason not to bump this timeout value up
significantly to a worst case scenario (ie multi-terrabyte volume).

Fixes bug: 1202007

Change-Id: I98c399f5d647e14f031018f7fc1cc43bb0d94c84