vet: Fix composite literal uses unkeyed fields warnings

Signed-off-by: Euan Harris <euan.harris@docker.com>

libnetwork/drivers/overlay/ostweaks_linux.go

@@ -7,9 +7,9 @@ import (
 )
 
 var ovConfig = map[string]*kernel.OSValue{
-	"net.ipv4.neigh.default.gc_thresh1": {"8192", checkHigher},
-	"net.ipv4.neigh.default.gc_thresh2": {"49152", checkHigher},
-	"net.ipv4.neigh.default.gc_thresh3": {"65536", checkHigher},
+	"net.ipv4.neigh.default.gc_thresh1": {Value: "8192", CheckFn: checkHigher},
+	"net.ipv4.neigh.default.gc_thresh2": {Value: "49152", CheckFn: checkHigher},
+	"net.ipv4.neigh.default.gc_thresh3": {Value: "65536", CheckFn: checkHigher},
 }
 
 func checkHigher(val1, val2 string) bool {

libnetwork/osl/namespace_linux.go

@@ -40,7 +40,7 @@ var (
 	loadBalancerConfig = map[string]*kernel.OSValue{
 		// expires connection from the IPVS connection table when the backend is not available
 		// more info: https://github.com/torvalds/linux/blob/master/Documentation/networking/ipvs-sysctl.txt#L126:1
-		"net.ipv4.vs.expire_nodest_conn": {"1", nil},
+		"net.ipv4.vs.expire_nodest_conn": {Value: "1", CheckFn: nil},
 	}
 )