Setting up Windows Agent in continous blessing mode after install.

This is required the clones-of-clones test and is the default mode of
operation for the linux agent. Since this doesn't affect any other
tests, it makes sense to have this be the default (and only) mode for
now.

Change-Id: I825d30fb5279c4b715de39d3ea2100b1e482dc21
Merge "Setting up Windows Agent in continous blessing mode after install."