[PATCH] Replace svn_path_join() in svn/diff-cmd.c

[[[
Replace deprecated svn_path_join().

* subversion/svn/cl.h
  (svn_cl__path_join): New.

* subversion/svn/util.c
  (svn_cl__path_join): Wrap svn_path_join().

* subversion/svn/diff-cmd.c
  (svn_cl__diff): Replace svn_path_join() with svn_cl__path_join() since
    the resulting path is allowed to be both uri and dirent.
  (summarize_xml, summarize_regular): Replace svn_path_join() with
    svn_uri_join(). Summarized diffs can only be performed between
    repos.

Patch by: Daniel Näslund <daniel{_AT_}longitudo.com>
Suggested by: julianf
]]]

svn_cl__path_join() is there to gather the cases that could not be
resolved.

/Daniel