take into account that f90wrap_version may be None in MetalWalls easyblock

[Crivella]

Fix exception caused by calling LoosVersion on f90wrap_version even when it is None

[boegel]

@boegelbot please test @ jsc-zen3
EB_ARGS="MetalWalls-21.06.1-foss-2023a.eb"

[boegel]

lgtm

[boegelbot]

@boegel: Request for testing this PR well received on jsczen3l1.int.jsc-zen3.fz-juelich.de

PR test command 'if [[ develop != 'develop' ]]; then EB_BRANCH=develop ./easybuild_develop.sh 2> /dev/null 1>&2; EB_PREFIX=/home/boegelbot/easybuild/develop source init_env_easybuild_develop.sh; fi; EB_PR=3468 EB_ARGS="MetalWalls-21.06.1-foss-2023a.eb" EB_REPO=easybuild-easyblocks EB_BRANCH=develop /opt/software/slurm/bin/sbatch --job-name test_PR_3468 --ntasks=8 ~/boegelbot/eb_from_pr_upload_jsc-zen3.sh' executed!

• exit code: 0
• output:

Submitted batch job 5032

Test results coming soon (I hope)...

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