Following from SERVER-46082 etc/perf.yml and etc/system_perf.yml can now be cleaned up a bit.

• source dsienv.sh can be removed
• setup-dsi-env.sh can be removed
• some of the shell.exec blocks can be merged, at least for perf.yml
• perf.yml has diverged between master and 4.2, for example mongod.log ends up in different directory. This should be reconciled to stable branches.
• In Microbenchmarks there are two mongod.log checks that are always green because they check files from dsi unittest-files. Pending future work on dsi libanalysis code, suggested solution is to just `rm -r dsi/bin/tests`
• Ryan: Prefer that also perf.yml uses run-dsi.
• I added a couple `set -o verbose` when troubleshooting bin/analysis.py. This could be removed I think.
• I think it's possibly related to perf.yml that analysis.py / mongod.log check isn't picking up the test start and end times from perf.json. As a workaround, I disabled the election related checks in analysis.common.yml.
• I bet boostrap.production isn't actually needed in perf.yml?
• Addition from team discussion:
  • Consolidate setupcluster into one DSI command 
  • Read from expansions.yml instead of what sysperf currently does to write runtimesecret.yml, etc.

For system_perf.yml, consider also renaming the yaml file expansions to match what is used in dsi:

• cluster -> infrastructure_provisioning
• setup -> mongodb_setup
• test -> test_control