rewrite system snapshot to java: removed obsoleted perl page
delta_canonical_lists_hashref() is unused

after snapshot_comparison_provider() removal
vercmp() is unused

after delta_canonical_lists_hashref() removal
missing_packages_for_session is not referenced anywhere
find_package_profile() is unused

after missing_packages_for_session_provider() removal
profile_packages_missing_from_channels() is unused

after missing_packages_for_session_provider() removal
channel_package_intersection_from_set() is unused

after missing_packages_for_session_provider() removal
create_from_system() is unused

after find_package_profile() removal
packages_in_channel_by_id_combo is unused

after profile_packages_missing_from_channels() removal
profile_canonical_package_list is unused

after profile_packages_missing_from_channels() removal
packages_not_available_from() is unused

after profile_packages_missing_from_channels() removal
copy_from() is unused

after create_from_system() removal
packages_by_name_arch() is unused

after packages_not_available_from() removal