Space current used by optional files shows space even for 0% downloaded files

### Step 1: Please describe your environment

* ZeroNet version: 0.6.2 rev3467
* Operating system: Linux 64bit Centos7
* Web browser: Firefox beta
* Tor status: error
* Opened port: opened

### Step 2: Describe the problem:

On the Files tab of the ZeroHello i see: "Used: 10.0 GB / 7.5 GB (119%)" and when i ticked & deleted some large files with status 0% (assume these are not downloaded and these are ones that are larger than the maximum limit i set when "Download and distribute all files" was ticked in zite (0) menu) then i refresh ZeroHello Files page and see "Used: 9.0 GB / 7.5 GB". So it decreased. Maybe ZeroHello should not count not downloaded files into limit as it is confusing?