datapath-windows: Solved BSOD when handling flows

datapath-windows: Solved BSOD when handling flows

OvsPrepareFlow() returns an error only when the new flow allocation
fails. In this case HandleFlowPut() should return error without trying
to free the flow, thus avoiding the BSOD.

Signed-off-by: Sorin Vinturis <svinturis@cloudbasesolutions.com>
Reported-by: Sorin Vinturis <svinturis@cloudbasesolutions.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/91
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>