Revert "make include statements trigger async conversion inside if/fo…

…r statements (fixes #372)"

This reverts commit 7d4716f.

Using an include is not (in and of itself) a request to turn a for-loop
async. It may be that some version of this fix is needed, but if so it needs to
be more carefully targeted.

Fixes #527; re-opens #372.

src/transformer.js

@@ -190,8 +190,7 @@ function convertStatements(ast) {
                node instanceof nodes.IfAsync ||
                node instanceof nodes.AsyncEach ||
                node instanceof nodes.AsyncAll ||
-               node instanceof nodes.CallExtensionAsync ||
-               node instanceof nodes.Include) {
+               node instanceof nodes.CallExtensionAsync) {
                 async = true;
                 // Stop iterating by returning the node
                 return node;