Revert "Tell the image deleter spec which image we're expecting to delete."

This reverts commit c1b275c6bd0ed2165ca00bf12d53604671627ee3.
Ensure that the selector we're looking for exists, and then find it.

We're now using the actual image's title attribute to detect the title for the image.
I think this makes sense.
CI against whatever is the latest Ruby version in 2.1.x
Test each extension in parallel on CI.