Migrate qemu_pipe_open_ns to virtio-vsock

goldfish_pipe (/dev/goldfish_pipe) is
going to be replaced with virtio-vsock.

Keep /dev/goldfish_pipe if virtio-vsock fails.

Bug: 169261468
Test: presubmit
Signed-off-by: Roman Kiryanov <rkir@google.com>
Change-Id: I4de058211d407156ff0baf5aec550a6cba3f1129
1 file changed