Fixes this bug:

    When setting 'keymap' twice the b:keymap_name variable isn't set. (Milan
    Berta, 2007 Mar 9) Has something to do with 'iminsert'.

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


*** src/digraph.c.orig	Thu Jul  5 22:09:38 2007
--- src/digraph.c	Thu Jul  5 22:10:07 2007
***************
*** 2351,2356 ****
--- 2351,2360 ----
      {
  	/* Stop any active keymap and clear the table. */
  	keymap_unload();
+ 	/* Remove internal variable b:keymap_name.  This cannot be done in
+ 	 * keymap_unload(), as keymap_unload() is also called by
+ 	 * ex_loadkeymap(). */
+ 	do_cmdline_cmd((char_u *)"unlet! b:keymap_name");
      }
      else
      {
***************
*** 2500,2506 ****
  
      ga_clear(&curbuf->b_kmap_ga);
      curbuf->b_kmap_state &= ~KEYMAP_LOADED;
-     do_cmdline_cmd((char_u *)"unlet! b:keymap_name");
  #ifdef FEAT_WINDOWS
      status_redraw_curbuf();
  #endif
--- 2504,2509 ----