pki_crypto: Correct error checking after RSA key generation

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
(cherry picked from commit a80547bdf9)

src/pki_crypto.c

@@ -529,7 +529,7 @@ int pki_key_generate_rsa(ssh_key key, int parameter){
 
 	BN_free(e);
 
-	if (rc == -1 || key->rsa == NULL)
+	if (rc <= 0 || key->rsa == NULL)
 		return SSH_ERROR;
 	return SSH_OK;
 }