[PATCH] cifs: cleanup of ifdefs usage so it is more consistent

And fix to not needlessly send new POSIX QFSInfo when server does not
explicitly claim support for the new protocol extensions. 

Signed-off-by: Steve French <(sfrench@us.ibm.com)>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>