7133476: (fs) Files.readAttributes throws NPE

[Alan Bateman]

Currently Files.readAttributes throws NPE rather than UOE on Mac OS X 
when invoked to read DOS attributes. This looks like an issue introduced 
upstream in the BSD porting project. To fix this requires removing 
BsdFileSystemProvider.readAttributes (the super class implementation 
does the right thing already). While I was there I also removed 
commented out code that should not be here. The webrev with the changes 
is here:

http://cr.openjdk.java.net/~alanb/7133476/webrev/

Thanks,
Alan.