Speed up scan_dir by uppercasing the name to search for outside the loop
and only comparing the mangled short name for SFN searches.
LFN searches only compare the long name case insensitively.
Use VFAT_IOCTL_READDIR_SHORT on vfat partitions from non-LFN code to
make sure that LFN's are invisible when they aren't needed.
Plug memory leak and page fault if you lredir'ed a non-existent
directory.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@725 7758b857-130e-0410-ab9c-d8735a528d18