webdav: skip test that fails with gccgo

Change-Id: Ibcb2fbb6a016046dd67e92372376f0f639979e37
Reviewed-on: https://go-review.googlesource.com/24484
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed