Virtual Codebase shows `RecursionError: maximum recursion depth exceeded` when full root is used during scanning

### Description

`Virtual Codebase` is showing `Recursion Error` upon using its Virtual Codebase , for scanning a this following [json file](https://drive.google.com/file/d/1okZlHwP0eziNY2ghQ3iwWwUZm3YUvEh7/view?usp=sharing) **(scanned with scancode toolkit version 2.x)**
The command used for scanning is `scancode --json-pp ../asd.json --from-json new.json`
The following are the exceptions raised:

### How To Reproduce
IMO the following error is raised when we are dealing with files where the `path` variable in the json file contains many sub directories. The json file which I attached in the link contains file with the following path `"/Users/sesser/code/nexb/scancode-toolkit/samples/README` .
`Actually I am not cent percent sure weather this is the cause of the following exception or not , but I noticed that this error is caused for such a kind of json files`

### System configuration
OS Ubuntu 18.04 ,Python 3.6

* What OS are you running on? (Windows/MacOS/Linux) linux
* What version of scancode-toolkit was used to generate the scan file? 3.1.2
* What installation method was used to install/run scancode? (pip/source download/other)source download