Use async version of mkdir-recursive, fix #1493

lib/handlers/patch.js

@@ -60,7 +60,16 @@ async function patchHandler (req, res, next) {
     const pathSplit = path.split('/')
     const directory = pathSplit.slice(0, pathSplit.length - 1).join('/')
     if (!fs.existsSync(directory)) {
-      fx.mkdirSync(directory, { recursive: true })
+      debug('PATCH -- mkdirp <%s>', directory)
+      await new Promise((resolve, reject) => {
+        fx.mkdir(directory, { recursive: true }, (err) => {
+          if (err) {
+            reject(err)
+          } else {
+            resolve()
+          }
+        })
+      })
     }
 
     // Patch the graph and write it back to the file
@@ -96,6 +105,7 @@ function readGraph (resource) {
         if (err.code === 'ENOENT') {
           fileContents = ''
           // Fail on all other errors
+          debug('PATCH to create')
         } else {
           return reject(error(500, `Original file read error: ${err}`))
         }