[IO] Worked around attempts to close unopened file descriptors in Parrot_io_open_unix() (Coverity CID #168).
[IO] Worked around attempts to close unopened file descriptors in
Parrot_io_open_unix() (Coverity CID #168).

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@44711 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot