Wrong HTTP error code when encountering full disk write error

[lghds]

Having reported #1691 to the respective client software projects, one of them asked me to point this out to you.

When radicale encounters a full disk while trying to fulfill a request, it responds with 401 Bad Request, while 507 Insufficient Storage would be more appropriate.

Steps to reproduce:

• 1: Clog the server's disk. This can be artificially achieved for example by querying free disk space with df -h and filling it up with fallocate -l clog_file

• 2: Try to add, edit or delete entries using a client software to trigger the error.

[pbiering]

make sense, will change the error code next