org-plot: Reset gnuplot process instead of killing it

org-plot.el (org-plot/gnuplot): Do not kill the gnuplot process. just
jump to end of buffer and rely on command to do the resetting job.

Without this patch, the gnuplot process associated to the gnuplot
buffer is killed before each batch of instructions from orgmode to
gnuplot.  With or without this patch, Org mode sends a reset
instruction to the gnuplot process as first instruction.

TINYCHANGE

lisp/org-plot.el

@@ -281,8 +281,7 @@ line directly before or after the table."
     (delete-other-windows)
     (when (get-buffer "*gnuplot*") ;; reset *gnuplot* if it already running
       (with-current-buffer "*gnuplot*"
-	(goto-char (point-max))
-	(gnuplot-delchar-or-maybe-eof nil)))
+	(goto-char (point-max))))
     (org-plot/goto-nearest-table)
     ;; set default options
     (mapc