
Make the fs commit-editor use memory more efficiently.  Specifically,
after the driver calls close_file, free any memory used for writing
file contents.

(struct file_baton):  add a subpool field.
(add_file, replace_file):  initialize file baton's subpool.
(apply_textdelta):  use file baton's subpool for streamy writes.
(close_file):  free the file baton's subpool.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@838862 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion