add sign/verify methods

Reviewed-by: Richard Levitte <levitte@openssl.org>

crypto/ec/ec_kmeth.c

@@ -65,7 +65,10 @@ static const EC_KEY_METHOD openssl_ec_key_method = {
     0,
     0,0,0,0,0,0,
     ossl_ec_key_gen,
-    ossl_ecdh_compute_key
+    ossl_ecdh_compute_key,
+    ossl_ecdsa_sign_setup,
+    ossl_ecdsa_sign_sig,
+    ossl_ecdsa_verify_sig
 };
 
 const EC_KEY_METHOD *default_ec_key_meth = &openssl_ec_key_method;