ldb: version 1.1.26

ldb: version 1.1.26

* let a timeout of -1 indicate no timeout for a given request
* fix memory leaks in pyldb ldb.search()
* build fixes
* improve pyldb ldb.search() help message
* add pyldb ldb.search_iterator() api
* add LDB_ATTR_FLAG_FORCE_BASE64_LDIF as optional argument
  to ldb_schema_attribute_add()
* add client support for LDB_CONTROL_DIRSYNC_EX

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>