* File.cs: In Move, throw IOException instead of ArgumentException if destination

	* File.cs: In Move, throw IOException instead of ArgumentException if destination
	  is a directory.
	* MonoIO.cs: In ExistsDirectory, return ERROR_PATH_NOT_FOUND instead of
	  ERROR_FILE_NOT_FOUND, since we are looking for a directory, not a file.

svn path=/trunk/mcs/; revision=24527