Revision 1626023

On the 'move-tracking-2' branch: Simplify editor shim usage by passing file
content in memory instead of in temporary files.

The shim code was leaving temporary files in /tmp. Managing temporary files
correctly (for example, cleaning up even in case of error) is difficult, and
handling of text content too big to fit in memory is unnecessary at this
stage of development.

* subversion/include/private/svn_editor3.h
  (svn_editor3__shim_fetch_func_t): Use a string buffer instead of a
    temporary file.

* subversion/libsvn_delta/compat3.c
  (change_node_t, ev3_file_baton): Use a string buffer instead of a
    temporary file. Get rid of the 'checksum' field.
  (process_actions,
   ev3_add_file,
   ev3_open_file,
   ev3_apply_textdelta,
   ev3_close_file,
   apply_change,
   editor3_put): Adjust accordingly.
  (ev3_open_delta_base, ev3_open_delta_target): Remove.

* subversion/libsvn_ra/ra_loader.c
  (fetch): Adjust accordingly.

* subversion/libsvn_repos/commit.c
  (fetch_func): Adjust accordingly.

* subversion/libsvn_wc/wc.h,
  subversion/libsvn_wc/util.c
  (svn_wc__fetch_func): Adjust accordingly.