Ensure dropbear is installed before disabling telnet (#920)

SVN-Revision: 5465

package/base-files/default/etc/init.d/telnet

@@ -2,7 +2,7 @@
 # Copyright (C) 2006 OpenWrt.org
 
 start() {
-	if awk -F: '/^root:/ && $2 !~ /\!/ {exit 1}' /etc/passwd 2>/dev/null; then telnetd -l /bin/login; fi
+	if awk -F: '/^root:/ && $2 !~ /\!/ {exit 1}' /etc/passwd 2>/dev/null && [ -x /usr/sbin/dropbear ]; then telnetd -l /bin/login; fi
 }
 
 stop() {