protect against subtly corrupted user objects

www/common/fileObject.js

@@ -295,7 +295,7 @@ define([
                     paths.push(p);
                 }
             };
-            if (path.length === 1) {
+            if (path.length === 1 && typeof(root) === 'object') {
                 Object.keys(root).forEach(function (key) {
                     var arr = root[key];
                     if (!Array.isArray(arr)) { return; }

www/common/mergeDrive.js

@@ -152,6 +152,7 @@ define([
                 var oldFo = FO.init(parsed.drive, {
                     Cryptpad: Cryptpad
                 });
+                oldFo.fixFiles();
                 var newData = Cryptpad.getStore().getProxy();
                 var newFo = newData.fo;
                 var newRecentPads = proxy.drive[Cryptpad.storageKey];