update RecConf/Configuration.py in line with 2016/2017/2018 patches for pgun

In line with !2148 (merged) and !2149 (merged), update run2-patches rec configuration to not rely on explicit sequence setting in appconfig, as this is prone to breaking. Discovered when trying to set up productions for 2017 and 2018 pgun.

@kreps @gcorti @cattanem

mentioned in merge request !2148 (merged)

added Simulation all-slots bug fix labels

• [2020-08-07 00:11] Validation started with lhcb-run2-patches#780
• [2020-08-07 00:12] Validation started with lhcb-run2-patches-dev4#413

removed all-slots label

merged

mentioned in commit ec60863c

added highlight label

changed title from update Configuration.py in line with 2016/2017/2018 patches for pgun to update RecConf/Configuration.py in line with 2016/2017/2018 patches for pgun

changed the description