Update cmssw-env to allow to use any cmssw image

[smuzaffar]

This now allows to use cmssw-env --cmsos cc7:amd64-bootstrap to uses /cvmfs/unpacked.cern.ch/registry.hub.docker.com/cmssw/cc7:amd64-bootstrap image

[smuzaffar]

please test

[cmsbuild]

A new Pull Request was created by @smuzaffar (Malik Shahzad Muzaffar) for branch IB/CMSSW_12_1_X/master.

@smuzaffar, @iarspider, @ddaina can you please review it and eventually sign? Thanks.
@perrotta, @dpiparo, @qliphy you are the release manager for this.
cms-bot commands are listed here

[smuzaffar]

+externals
we will merge it once 12.1.0.pre4 is released

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next IB/CMSSW_12_1_X/master IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @perrotta, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-766caa/19464/summary.html
COMMIT: 7141ced
CMSSW: CMSSW_12_1_X_2021-10-06-2300/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmsdist/7369/19464/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 40
• DQMHistoTests: Total histograms compared: 3219394
• DQMHistoTests: Total failures: 5
• DQMHistoTests: Total nulls: 1
• DQMHistoTests: Total successes: 3219366
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: -0.004 KiB( 39 files compared)
• DQMHistoSizes: changed ( 312.0 ): -0.004 KiB MessageLogger/Warnings
• Checked 169 log files, 37 edm output root files, 40 DQM output files
• TriggerResults: no differences found