Drivers: hv: vmbus: Fix a bug in the error path in vmbus_open()

commit 40384e4b

 upstream.

Correctly rollback state if the failure occurs after we have handed over
the ownership of the buffer to the host.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>