ipvs: only attempt setting of sysctlconnreuse on supported kernels

This builds on previous work but only sets the sysctlConnReuse value
if the kernel is known to be above 4.19. To avoid calling GetKernelVersion
twice, I store the value from the CanUseIPVS method and then check the version
constraint at time of expected sysctl call.

Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>

cmd/kube-proxy/app/server_others.go

@@ -276,6 +276,7 @@ func newProxyServer(
 				healthzServer,
 				config.IPVS.Scheduler,
 				config.NodePortAddresses,
+				kernelHandler,
 			)
 		} else {
 			var localDetector proxyutiliptables.LocalTrafficDetector
@@ -306,6 +307,7 @@ func newProxyServer(
 				healthzServer,
 				config.IPVS.Scheduler,
 				config.NodePortAddresses,
+				kernelHandler,
 			)
 		}
 		if err != nil {