Restart dockerd after successful file upload

[killenheladagen]

Just as when changing a VAPIX parameter, completing a file upload over HTTP will restart dockerd.

Checklist before requesting a review

• I have performed a self-review of my own code
• I have verified that the code builds perfectly fine on my local system
• I have added tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have verified that my code follows the style already available in the repository
• I have made corresponding changes to the documentation

[madelen-at-work]

Add a description of the change in the PR body - otherwise ok