Fixes this bug:

    ":e fold.c" then ":sp fold.c" results in folds of original window to
    disappear. (Akita Noek)

When reloading a file, Vim re-uses the buffer and in this connection calls
buffer.c:buf_freeall().  buf_freeall() clears the folds in all windows showing
the buffer, so we need to restore them by calling fold.c:foldUpdateAll() for
each window showing the buffer.  Manual folds are not restored, as the file
might have changed and we don't know whether they are still legal.

Created by Martin Toft <mt@martintoft.dk> during Google Summer of Code 2007.


Index: src/ex_cmds.c
===================================================================
RCS file: /cvsroot/vim/vim7/src/ex_cmds.c,v
retrieving revision 1.93
diff -c -r1.93 ex_cmds.c
*** src/ex_cmds.c	25 Jul 2007 20:56:39 -0000	1.93
--- src/ex_cmds.c	18 Aug 2007 18:27:49 -0000
***************
*** 3584,3592 ****
  	curwin_init();
  
  #ifdef FEAT_FOLDING
! 	/* It's like all lines in the buffer changed.  Need to update
  	 * automatic folding. */
! 	foldUpdateAll(curwin);
  #endif
  
  	/* Change directories when the 'acd' option is set. */
--- 3584,3603 ----
  	curwin_init();
  
  #ifdef FEAT_FOLDING
! 	/* It's possible that all lines in the buffer changed.  Need to update
  	 * automatic folding. */
! # ifdef FEAT_WINDOWS
! 	{
! 	    win_T	    *win;
! 	    tabpage_T	    *tp;
! 	    FOR_ALL_TAB_WINDOWS(tp, win)
! 		if (win->w_buffer == curbuf)
! 		    foldUpdateAll(win);
! 	}
! # else
! 	if (curwin->w_buffer == curbuf)
! 	    foldUpdateAll(curwin);
! # endif
  #endif
  
  	/* Change directories when the 'acd' option is set. */