openvswitch: Remove unnecessary version.h inclusion

version.h inclusion is not necessary as detected by versioncheck.

Signed-off-by: Syam Sidhardhan <s.syam@samsung.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>