Disable telnet in favor of passwordless SSH

This enables passworldless login for root via SSH whenever no root
password is set (e.g. after reset, flashing without keeping config
or in failsafe) and removes telnet support alltogether.

Signed-off-by: Steven Barth <steven@midlink.org>

SVN-Revision: 46809

package/network/services/dropbear/patches/610-skip-default-keys-in-custom-runs.patch

@@ -0,0 +1,18 @@
+--- a/svr-runopts.c
++++ b/svr-runopts.c
+@@ -475,6 +475,7 @@ void load_all_hostkeys() {
+ 		m_free(hostkey_file);
+ 	}
+ 
++	if (svr_opts.num_hostkey_files <= 0) {
+ #ifdef DROPBEAR_RSA
+ 	loadhostkey(RSA_PRIV_FILENAME, 0);
+ #endif
+@@ -486,6 +487,7 @@ void load_all_hostkeys() {
+ #ifdef DROPBEAR_ECDSA
+ 	loadhostkey(ECDSA_PRIV_FILENAME, 0);
+ #endif
++	}
+ 
+ #ifdef DROPBEAR_DELAY_HOSTKEY
+ 	if (svr_opts.delay_hostkey) {