update OpenMPI easyblock to fix sanity check for Clang-based compilers

[zemu-unile]

Clang compilers always have the same output when using --version. There is no different information when using C++ or Fortran compilers.

e.g.

$ clang++ --version
clang version 11.0.1
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /software/all/Clang/11.0.1-GCCcore-10.2.0/bin

[boegel]

Test report by @boegel

Overview of tested easyconfigs (in order)

• SUCCESS OpenMPI-4.1.1-intel-compilers-2021.4.0.eb
• SUCCESS OpenMPI-3.1.4-GCC-8.3.0.eb
• SUCCESS PMIx-4.2.4-GCCcore-12.3.0.eb
• SUCCESS UCC-1.2.0-GCCcore-12.3.0.eb
• SUCCESS OpenMPI-4.1.5-GCC-12.3.0.eb

Build succeeded for 5 out of 5 (3 easyconfigs in total)
node3115.skitty.os - Linux RHEL 8.6, x86_64, Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz (skylake_avx512), Python 3.6.8
See https://gist.github.com/boegel/48ae9fbce77acee50eab5d623b827466 for a full test report.

[boegel]

lgtm