Follow-up to r951859. Use the correct diff header for paths that are modified without tree changes.
Follow-up to r951859. Use the correct diff header for paths that are
modified without tree changes.

* subversion/libsvn_client/diff.c
  (print_git_diff_header): Write the 'diff --git ...' line even if
    there are no tree changes.
  (diff_content_changed): Use the correct diff label for paths with no
    tree changes.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion