virtiofsd: Drop -o no_posix_lock

The C implementation of virtiofsd had some kind of limited support
for remote POSIX locks that was causing some workflows to fail with
kata. Commit 432f9bea6e hard coded `-o no_posix_lock` in order
to enforce guest local POSIX locks and avoid the issues.

We've switched to the rust implementation of virtiofsd since then,
but it emits a warning about `-o` being deprecated.

According to https://gitlab.com/virtio-fs/virtiofsd/-/issues/53 :

   The C implementation of the daemon has limited support for
   remote POSIX locks, restricted exclusively to non-blocking
   operations. We tried to implement the same level of
   functionality in #2, but we finally decided against it because,
   in practice most applications will fail if non-blocking
   operations aren't supported.

   Implementing support for non-blocking isn't trivial and will
   probably require extending the kernel interface before we can
   even start working on the daemon side.

There is thus no justification to pass `-o no_posix_lock` anymore.

Signed-off-by: Greg Kurz <groug@kaod.org>

src/runtime/virtcontainers/virtiofsd.go

@@ -187,9 +187,6 @@ func (v *virtiofsd) args(FdSocketNumber uint) ([]string, error) {
 		"--syslog",
 		// cache mode for virtiofsd
 		"-o", "cache=" + v.cache,
-		// disable posix locking in daemon: bunch of basic posix locks properties are broken
-		// apt-get update is broken if enabled
-		"-o", "no_posix_lock",
 		// shared directory tree
 		"-o", "source=" + v.sourcePath,
 		// fd number of vhost-user socket

src/runtime/virtcontainers/virtiofsd_test.go

@@ -79,12 +79,12 @@ func TestVirtiofsdArgs(t *testing.T) {
 		cache:      "none",
 	}
 
-	expected := "--syslog -o cache=none -o no_posix_lock -o source=/run/kata-shared/foo --fd=123"
+	expected := "--syslog -o cache=none -o source=/run/kata-shared/foo --fd=123"
 	args, err := v.args(123)
 	assert.NoError(err)
 	assert.Equal(expected, strings.Join(args, " "))
 
-	expected = "--syslog -o cache=none -o no_posix_lock -o source=/run/kata-shared/foo --fd=456"
+	expected = "--syslog -o cache=none -o source=/run/kata-shared/foo --fd=456"
 	args, err = v.args(456)
 	assert.NoError(err)
 	assert.Equal(expected, strings.Join(args, " "))