[PATCH] Replace svn_path_join() in libsvn_client/merge.c

[[[
Remove use of the deprecated svn_path_join().

* subversion/libsvn_client/merge.c
  (record_mergeinfo_for_dir_merge, find_unmerged_mergeinfo):
    Replace svn_path_join() with svn_uri_join(). All "base" parameters
      are repos relative paths.
]]]

When joining source_repos_rel_path and target_repos_rel_path a leading
'/' is stripped from the second component. svn_dirent_uri.h says that we
should use svn_uri_basename() or svn_uri_strip_ancestor() when joining a
dirent to an uri. But basename() only gives us the last part and
strip_ancestor() depends on the two paths both beeing either relative or
absolute. Just stripping the '/' seems easier to understand to me.

/Daniel