On the invoke-diff-cmd-feature branch: Fix variable declaration and
initialization.  Update help info.

* subversion/libsvn_client/diff.c

  (set_up_diff_cmd_and_options): Fix variable declaration and
    intialization.

* subversion/libsvn_subr/config_file.c

  (invoke-diff-cmd): Update help info.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/invoke-diff-cmd-feature@1538088 13f79535-47bb-0310-9956-ffa450edef68