With ansible 2.9.27 (operator-sdk v1.27.0) then the reverse filter
returns an iterator so we need to cast it to list.
The behavior doesn't exist when using a more recent operator-sdk
version like v1.34.0 (ansible-core 2.15.8) but using the list
filter on that version works too (even if not needed)
"sorted_old_postgres_pods": "<list_reverseiterator object at 0x7f539eaa5610>"
Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>