Remove gems that should come in with refinery

Add full structure to dummy field in page_images

Convert specs to RSpec 2.99.0 syntax with Transpec

This conversion is done by Transpec 2.2.4 with the following command:
    transpec

Remove -1 parameter explicitly

-1 parameter used to detect all images deleted was not in proper format
for strong parameters.

Be more explicit about -1 removal