Corrects argument order in validationError.

Author: tcr

src/error/syntaxError.js

@@ -58,9 +58,9 @@ export function syntaxError(
  * returns an error containing the message, without context.
  */
 export function validationError(
-  message: string,
+  source: ?Source,
   node: ASTNode,
-  source: ?Source
+  message: string,
 ): GraphQLError {
   const position = node.loc ? node.loc.start : null;
   if (position == null || source == null) {

src/utilities/buildASTSchema.js

@@ -305,28 +305,28 @@ export function buildASTSchema(
   function produceInputType(typeNode: TypeNode): GraphQLInputType {
     const type = produceType(typeNode);
     invariant(isInputType(type),
-      validationError('Expected Input type', typeNode, source));
+      validationError(source, typeNode, 'Expected Input type'));
     return (type: any);
   }
 
   function produceOutputType(typeNode: TypeNode): GraphQLOutputType {
     const type = produceType(typeNode);
     invariant(isOutputType(type),
-      validationError('Expected Output type', typeNode, source));
+      validationError(source, typeNode, 'Expected Output type'));
     return (type: any);
   }
 
   function produceObjectType(typeNode: TypeNode): GraphQLObjectType {
     const type = produceType(typeNode);
     invariant(type instanceof GraphQLObjectType,
-      validationError('Expected Object type', typeNode, source));
+      validationError(source, typeNode, 'Expected Object type'));
     return type;
   }
 
   function produceInterfaceType(typeNode: TypeNode): GraphQLInterfaceType {
     const type = produceType(typeNode);
     invariant(type instanceof GraphQLInterfaceType,
-      validationError('Expected Interface type', typeNode, source));
+      validationError(source, typeNode, 'Expected Interface type'));
     return type;
   }