sdcard: Remove lower case squashing of file names

sdcard daemon will now create new files and directories using
the actual name passed in by the client.
For existing files, sdcard will do case insensitive matching
when case sensitive lookup fails.

Change-Id: I89f995ea01beb2c63a9b36943dbcfaa16e7cd972
Signed-off-by: Mike Lockwood <lockwood@android.com>