CBQE-2488, CBQE-2504: fixed auto_failover, soft-restart code for windows in system tests

If couchbase services already stopped after autofailover then current
soft-restart failed with && operator as start command doesn't invoked

Administrator@WIN-26PC57KC7NB ~
$ net stop couchbaseserver && net start couchbaseserver
The CouchbaseServer service is not started.

More help is available by typing NET HELPMSG 3521.

Administrator@WIN-26PC57KC7NB ~
$ net stop couchbaseserver || net start couchbaseserver
The CouchbaseServer service is not started.

More help is available by typing NET HELPMSG 3521.

The CouchbaseServer service is starting.
The CouchbaseServer service was started successfully.

Change-Id: I504f58911bc32250de31718f6fa044ba0f5b73d0
Reviewed-on: http://review.couchbase.org/43635
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>