catch all errors

lib/server.js

@@ -522,7 +522,7 @@ WalletService.prototype._selectTxInputs = function(txp, cb) {
       return cb(new ClientError('DUSTAMOUNT', 'Amount below dust threshold'));
     }
 
-    return cb(error);
+    return cb(bitcoreError || new Error('Could not select tx inputs'));
   });
 };