correct format hint

lib/rasha.js

@@ -71,8 +71,8 @@ RSA.generate = function (opts) {
       }
 
       return {
-        private: RSA.importSync({ pem: keypair.private, format: priv.format })
-      , public: RSA.importSync({ pem: keypair.public, format: pub.format, public: true })
+        private: RSA.importSync({ pem: keypair.private, format: priv.type })
+      , public: RSA.importSync({ pem: keypair.public, format: pub.type, public: true })
       };
     });
   });