Replace the usage of the old svn_wc__open_writable_base() function that we
already used before wc-ng's pristine store, with a new
svn_wc__db_pristine_prepare_install() function.

This patch moves a bit of code in preparation for more refactoring of this
logic.

* subversion/libsvn_wc/adm_crawler.c
  (svn_wc__internal_transmit_text_deltas): Update caller.

* subversion/libsvn_wc/adm_files.c
  (svn_wc__open_writable_base): Remove function. Move implementation to
    svn_wc__db_pristine_prepare_install().

* subversion/libsvn_wc/adm_files.h
  (svn_wc__open_writable_base): Remove function.

* subversion/libsvn_wc/externals.c
  (apply_textdelta): Update caller.

* subversion/libsvn_wc/update_editor.c
  (lazy_target_baton): Remove unneeded baton.
  (lazy_open_target): Directly use handler baton instead
    of a baton with the same info.

* subversion/libsvn_wc/wc_db.h
  (svn_wc__db_pristine_prepare_install): New function.

* subversion/libsvn_wc/wc_db_pristine.c
  (svn_wc__db_pristine_prepare_install): New function. Implementation copied
    from svn_wc__open_writable_base.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1577109 13f79535-47bb-0310-9956-ffa450edef68