ipv4: remove unnecessary double quotations from test messages

Change-Id: If1243dd2d79824933d896a8c4b31db8c247d0c21
Reviewed-on: https://go-review.googlesource.com/3561
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/ipv4/multicastsockopt_test.go b/ipv4/multicastsockopt_test.go
index 9f599fa..c76dbe4 100644
--- a/ipv4/multicastsockopt_test.go
+++ b/ipv4/multicastsockopt_test.go
@@ -27,11 +27,11 @@
 func TestPacketConnMulticastSocketOptions(t *testing.T) {
 	switch runtime.GOOS {
 	case "nacl", "plan9", "solaris":
-		t.Skipf("not supported on %q", runtime.GOOS)
+		t.Skipf("not supported on %s", runtime.GOOS)
 	}
 	ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagMulticast|net.FlagLoopback)
 	if ifi == nil {
-		t.Skipf("not available on %q", runtime.GOOS)
+		t.Skipf("not available on %s", runtime.GOOS)
 	}
 
 	m, ok := nettest.SupportsRawIPSocket()
@@ -67,14 +67,14 @@
 func TestRawConnMulticastSocketOptions(t *testing.T) {
 	switch runtime.GOOS {
 	case "nacl", "plan9", "solaris":
-		t.Skipf("not supported on %q", runtime.GOOS)
+		t.Skipf("not supported on %s", runtime.GOOS)
 	}
 	if m, ok := nettest.SupportsRawIPSocket(); !ok {
 		t.Skip(m)
 	}
 	ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagMulticast|net.FlagLoopback)
 	if ifi == nil {
-		t.Skipf("not available on %q", runtime.GOOS)
+		t.Skipf("not available on %s", runtime.GOOS)
 	}
 
 	for _, tt := range rawConnMulticastSocketOptionTests {
@@ -158,7 +158,7 @@
 		switch runtime.GOOS {
 		case "freebsd", "linux":
 		default: // platforms that don't support IGMPv2/3 fail here
-			t.Logf("not supported on %q", runtime.GOOS)
+			t.Logf("not supported on %s", runtime.GOOS)
 			return
 		}
 		t.Error(err)