Changes to allow Samba to return the same error code as Windows NT.

Changes to allow Samba to return the same error code as Windows NT.
Takes care of the cases where a Windows program is parsing a pathname
component by component and expects 2 different errors.
ERRbadpath - if a component in the path doesn't exist.
ERRbaddirectory - if a component in the path exists but is not a directory.
Extra error code added to smb.h to support this.
Code based on suggestions from "Christian Groessler" <chris@fast-ag.de>.

Jeremy (jallison@whistle.com)
(This used to be commit 28b3c6db8a81b41b448a4f3cd98e9cd2c4b5fb2e)