apparmor: remove useless aafs_create_symlink

commit 1180b4c7 ("apparmor: fix dangling symlinks to policy
rawdata after replacement") reworked how the rawdata symlink is
handled but failedto remove aafs_create_symlink which was reduced to a
useles stub.

Fixes: 1180b4c7 ("apparmor: fix dangling symlinks to policy rawdata after replacement")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: John Johansen <john.johansen@canonical.com>