lxc-test-symlink: add a test using absolute symlink

This would have caught the regression last night.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

src/tests/lxc-test-symlink

@@ -50,6 +50,7 @@ cat >> /var/lib/lxc/symtest1/config << EOF
 lxc.mount.entry = $dirname opt/xxx/dir none bind,create=dir
 lxc.mount.entry = $fname opt/xxx/file none bind,create=file
 lxc.mount.entry = $fname2 opt/xxx/file2 none bind
+lxc.mount.entry = $dirname /var/lib/lxc/symtest1/rootfs/opt/xxx/dir2 none bind,create=dir
 EOF
 
 # Regular - should succeed