This is required for the next commit. Also, drop CI_RETRY_EXE before
"dnf install", because it requires getopt, which will only be installed
later on via util-linux
This should avoid errors when running it twice. For example, network
errors on the second invocation of 'apt update'; or unguarded
modifications such as APPEND_APT_SOURCES_LIST, which will append the
same string repeatedly.
The base install may be run twice in Cirrus CI with dockerfiles, or
locally when running twice with DANGER_RUN_CI_ON_HOST specified.