Pass call type in from/toGraphQL

Currently types are ignored and not getting passed in `callsFromGraphQL`
or `callsToGraphQL`.
This results in dangerous output in `toGraphQL`, in which all calls have
type null. This can cause problems when using non-scalar types (like
enum).
Example can be found
[here](facebook#1256).

src/query/callsFromGraphQL.js

@@ -26,6 +26,7 @@ const invariant = require('invariant');
 type CallOrDirective = {
   name: string,
   value: ?ConcreteValue,
+  type?: ?string,
 };
 
 /**
@@ -43,6 +44,7 @@ function callsFromGraphQL(
   for (let ii = 0; ii < callsOrDirectives.length; ii++) {
     const callOrDirective = callsOrDirectives[ii];
     let {value} = callOrDirective;
+    let {type} = callOrDirective.metadata;
     if (value != null) {
       if (Array.isArray(value)) {
         value = value.map(arg => getCallValue(arg, variables));
@@ -53,7 +55,7 @@ function callsFromGraphQL(
         value = getCallValue(value, variables);
       }
     }
-    orderedCalls.push({name: callOrDirective.name, value});
+    orderedCalls.push({name: callOrDirective.name, value, type});
   }
   return orderedCalls;
 }

src/query/callsToGraphQL.js

@@ -22,14 +22,14 @@ const QueryBuilder = require('QueryBuilder');
  * Convert from plain object `{name, value}` calls to GraphQL call nodes.
  */
 function callsToGraphQL(calls: Array<Call>): Array<ConcreteCall> {
-  return calls.map(({name, value}) => {
+  return calls.map(({name, value, type}) => {
     let concreteValue = null;
     if (Array.isArray(value)) {
       concreteValue = value.map(QueryBuilder.createCallValue);
     } else if (value != null)  {
       concreteValue = QueryBuilder.createCallValue(value);
     }
-    return QueryBuilder.createCall(name, concreteValue);
+    return QueryBuilder.createCall(name, concreteValue, type);
   });
 }