While we should be aware of spack changes, let's have the nightly tests
exercise mochi stuff.  We'll update spack when spack releases happen.

- file backend could have different dependencies

- must build benchmarks twice, once with pmdk back end and once with
  file backend
- rpath in executable keeps a fixed library linkage otherwise

- includes two bake builds: one with pmdk, one with file backend
- actual runs do not work yet due to a mount problem

- set $HOME to avoid perturbing ~/ config files for the user running this script
- remove deprecated --dirty and LD_PRELOAD hacks
- remove explicit set of SPACK_ROOT in favor of variable set by spack itself
- other misc streamlining improvements

- this is a workaround to strip unusual characters out of output so that
  the mailx command will put it inline with message

idiomatic spack sets SPACK_ROOT and sources env based on that

Whoops: while I was here, build ior-mobject which will pull in just
about every one of our SDS packages

- build and run against mvapich with verbs support
- use newer gcc
- don't do dirty builds

- no longer any need for fork of spack (PR merged)
- no longer any need for @develop libfabric

- also rename some scripts and email headings for consistency

- also normalize test order and labels with other platforms

- the purpose is to test the new wait_fd capability in verbs;ofi_rxm

- previous patch to work around bad interaction with bash scripts was no
  longer working

this change has been upstreamed in spack

- will open PR for spack for long term fix

- use local pwd for tmp files (easier cleanup in CI environments)
- manually generate repos.yaml without perturbing ~/.spack
- copy packages.yaml into place without perturbing ~/.spack