Add more cd9660/FFS makefs testcases

General changes:

• Parameterize out the mount command.
• Use mtree to verify the contents of an image (check_image_contents) instead of using diff (diff verifies content, but not file metadata).
• Move common logic out to functions (common_cleanup, mount_image, check_image_contents)
• Add stub testcases for makefs -D (crashes with SIGBUS, similar to bug # 192839)
• Add a note about the ISO-9660 and rockridge specs
• Add testcases that exercise:
  • Creating disk images from an mtree and multiple directories.
  • -F flag use (not really an extensive testcase right now)

cd9660-specific test changes:

• Remove an XXX comment about symlinks; I forgot that non-rockridge images turn symlinks into hardlinks.
• Add testcases that exercise:
  • -o allow-deep-trees
  • -o allow-max-name stub testcase (doesn't seem to be implemented in makefs)
  • -o preparer (existence in image; not conformance to spec)
  • -o publisher (existence in image; not conformance to spec)
  • -o rockridge (basic)

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division