Fix an uninitialized variable access in callers of parse_msdfs_symlink

Fix an uninitialized variable access in callers of parse_msdfs_symlink

At least form_junctions() does not initialize refcount, and I don't see it in
get_referred_path(). For the latters, the callers might initialize it. But even
if they did, I think parse_msdfs_symlink() should unconditionally return the
number of referrals it found. I don't think it makes sense to count them up
from somewhere else.