New folder option should be inactive when full access is locked

[Evan Wang]

$ adb shell system-image-cli -i
current build number: 31
device name: mako
channel: ubuntu-touch/rc-proposed/ubuntu-pd
last update: 2015-09-16 03:32:11
version version: 31
version ubuntu: 20150915
version device: 20150911
version custom: 20150915

File Manager version: 0.4.386

Steps to reproduce:
1. Launch File Manager app
2. Tap on the drop-down menu from top right corner, make sure "Unlock full access" option is visible with lock icon
3. Tap on New Folder
4. Create folder dialog appears and requesting a name for new folder
5. Enter a name and tap on OK,

Actual results:
After entered a name for new folder and tap on OK, the dialog will disappear, but no new folder created
So my understanding is that it's unable to create new folder when full access is locked, probably it's more reasonable if New Folder option will not active until full access has been unlocked, or a prompt popup to tell the user to unlock full access first.