Revert "docs: retrospectively add XS_DIRECTORY_PART to the xenstore protocol..."

Jürgen Groß <jgross@suse.com> points out that this is entirely wrong.

Adding the "Backport" tag so we find this revert too.

This reverts commit d34dc88098.

Backport: 4.9+
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

docs/misc/xenstore.txt

@@ -125,9 +125,8 @@ Values commonly included in payloads include:
 
 
 
-The following are the actual type values defined in io/xs_wire.h
-(omitting the XS_ prefix), including the request and reply payloads
-as applicable:
+The following are the actual type values, including the request and
+reply payloads as applicable:
 
 
 ---------- Database read, write and permissions operations ----------
@@ -153,14 +152,6 @@ DIRECTORY		<path>|			<child-leaf-name>|*
 	leafnames.  The resulting children are each named
 	<path>/<child-leaf-name>.
 
-DIRECTORY_PART		<path>|<index|>		<child-leaf-name>|*
-	Performs the same function as DIRECTORY, but returns a
-	sub-list of children starting at <index> in the overall
-	child list and less than or equal to XENSTORE_PAYLOAD_MAX
-	octets in length. If <index> is beyond the end of the
-	overall child list then the returned sub-list will be
-	empty.
-
 GET_PERMS	 	<path>|			<perm-as-string>|+
 SET_PERMS		<path>|<perm-as-string>|+?
 	<perm-as-string> is one of the following