Panic when admin tries to delete a user with `purge=true`

[dhruvmanila]

Description

As an admin, when you try to delete a user with purge=true, it panics. This is done using the API, so the url would be something like https://localhost:3000/api/v1/admin/users/foo?purge=true.

Gitea Version

c0f5111

Can you reproduce the bug on the Gitea demo site?

No

Log Gist

https://gist.github.com/dhruvmanila/9c8a2c45dd31247dd993cfbfa3db2922

Screenshots

No response

Git Version

No response

Operating System

macOS

How are you running Gitea?

Running locally using make watch command on the command-line.

Steps to reproduce:

1. Create an admin user
2. Create 2 non-admin user
3. Using httpie, run http :3000/api/v1/admin/users/{username}?purge=false --auth username:password for the first user and then use purge=true for the second user

When purge is true, it panics.

Database

PostgreSQL