Change some of the SVN-ACTION DAV logging names to match the svnserve

Change some of the SVN-ACTION DAV logging names to match the svnserve
command set.

Justification:

- 1.5 already contains backwards-incompatible changes to the logging
  format; this (if it gets backported) is a reasonable time to make
  other bikesheddy changes.

- The svnserve command set is a good vocabulary for svn operational
  actions; there's no reason to have a second vocabulary that is
  mostly but not entirely the same.

- When svnserve grows logging, it would make sense to use its command
  set as the vocabulary; making these format changes would allow the
  two servers to share the same log format.

The specific changes made:

 list-dir => get-dir
 revprop-change => change-rev-prop
 revprop-list => rev-proplist
 blame => get-file-revs
 remote-status => status
 diff-or-merge => diff

(I would also like to get rid of prop-list, and in exchange add
props?/text? fields to get-dir and a new get-file.)

(It may also be worth logging get-locations and
get-location-segments, especially given that the latter has
complicated performance characteristics.)

* subversion/mod_dav_svn/deadprops.c
  (save_value): revprop-change => change-rev-prop
  (db_first-name): revprop-list => rev-proplist

* subversion/mod_dav_svn/reports/file-revs.c
  (dav_svn__file_revs_report): blame => get-file-revs

* subversion/mod_dav_svn/reports/update.c
  (dav_svn__update_report): diff-or-merge => diff

* subversion/mod_dav_svn/repos.c
  (do_walk): list-dir => get-dir

* tools/server-side/svn_dav_log_parse.py
  Update docstring; adjust everywhere.

* tools/server-side/test_svn_dav_log_parse.py
  Adjust everywhere.

git-svn-id: http://svn.collab.net/repos/svn/trunk@29412 612f8ebc-c883-4be0-9ee0-a4e9ef946e3a