Profile picture survives deletion and recreation of account

[minils]

Steps to reproduce

1. Create account X and set a profile picture
2. Delete the account X
3. Create a new account X with the same username

Expected behaviour

The profile picture is reset.

Actual behaviour

The profile picture of the old account is visible

Server configuration

Operating system: Fedora 26

Web server: Apache/2.4.27

Database: MariaDB/10.1.26-2.fc26

PHP version: 7.1.9-2.fc26

Nextcloud version: 12.0.3

Updated from an older Nextcloud/ownCloud or fresh install: Update from 12.0.2

Where did you install Nextcloud from: nextcloud.com zip file

Signing status:

List of activated apps:
Enabled:

• activity: 2.5.2
• apporder: 0.4.0
• bruteforcesettings: 1.0.2
• calendar: 1.5.5
• comments: 1.2.0
• contacts: 1.5.3
• dav: 1.3.0
• federatedfilesharing: 1.2.0
• federation: 1.2.0
• files: 1.7.2
• files_downloadactivity: 1.1.1
• files_markdown: 2.0.1
• files_pdfviewer: 1.1.1
• files_sharing: 1.4.0
• files_texteditor: 2.4.1
• files_trashbin: 1.2.0
• files_versions: 1.5.0
• files_videoplayer: 1.1.0
• firstrunwizard: 2.1
• gallery: 17.0.0
• logreader: 2.0.0
• lookup_server_connector: 1.0.0
• metadata: 0.5.0
• nextcloud_announcements: 1.1
• notes: 2.3.1
• notifications: 2.0.0
• oauth2: 1.0.5
• password_policy: 1.2.2
• previewgenerator: 1.0.6
• provisioning_api: 1.2.0
• serverinfo: 1.2.0
• sharebymail: 1.2.0
• survey_client: 1.0.0
• systemtags: 1.2.0
• tasks: 0.9.5
• theming: 1.3.0
• twofactor_backupcodes: 1.1.1
• twofactor_totp: 1.3.1
• updatenotification: 1.2.0
• workflowengine: 1.2.0

[rullzer]

Mmmm we should probabaly listen to some hook ;) Let me take care of this.

[rullzer]

PR in #6668