textbuffer_view_remove_line() fixes (with a small kludge..)

git-svn-id: http://svn.irssi.org/repos/irssi/trunk@1741 dbcabf3a-b0e7-0310-adc4-f8d773084564

src/fe-text/textbuffer.c

@@ -308,6 +308,8 @@ void textbuffer_remove(TEXT_BUFFER_REC *buffer, LINE_REC *line)
 			line->next : line->prev;
 	}
 
+        line->prev = line->next = NULL;
+
 	buffer->lines_count--;
         textbuffer_line_unref(buffer, line);
 }