Fix image deletion issue caused by S3 storage fix

[benjaoming]

Fixes #911

This fixes some code that may have been introduced through a merging issue. I don't know -- but it addresses something that was assumed fixed and is already in the changelog, so will not add it again :)

[codecov]

Codecov Report

Merging #912 into master will increase coverage by 0.06%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #912      +/-   ##
==========================================
+ Coverage   74.24%   74.31%   +0.06%     
==========================================
  Files         106      106              
  Lines        4330     4326       -4     
==========================================
  Hits         3215     3215              
+ Misses       1115     1111       -4

Impacted Files	Coverage Δ
src/wiki/plugins/images/models.py	56.47% <0%> (+2.53%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a144a31...36c5dd6. Read the comment docs.

[benjaoming]

I'm waiting to see if the CodeCov report that was posted earlier will eventually update or if there's a bug with their system..

[benjaoming]

Bug reported to CodeCov yesterday, but I give up about the comment not being updated.