enhance Gurobi easyblock to allow using $EB_GUROBI_LICENSE_FILE environment variable

[Micket]

(created using eb --new-pr)

[Micket]

erh.. this got troublesome.

The old code has the checks for self.cfg['license_file'] in install_step, so it was broken for --module-only since self.license_file is in that case never assigned.

But now the init step requires the existance of a license file, which breaks the unit tests somehow. I guess i'll just move those checks to the install step. The sanity check already includes a final check as well, so it's all pretty overkill anyway. I moved it into the dir, install step and only when copying is attempted, otherwise, the install step wouldn't care whether the file exists or not. The sanity check takes care of the final check anyway.

[jfgrimm]

Test report by @jfgrimm

Overview of tested easyconfigs (in order)

• SUCCESS Gurobi-9.0.0.eb
• SUCCESS Gurobi-9.0.3-GCCcore-10.2.0.eb
• SUCCESS Gurobi-9.1.2.eb
• SUCCESS Gurobi-9.5.0-GCCcore-10.3.0.eb
• SUCCESS Gurobi-9.5.2-GCCcore-11.3.0.eb

Build succeeded for 5 out of 5 (5 easyconfigs in total)
himem02.pri.viking.alces.network - Linux CentOS Linux 7.9.2009, x86_64, Intel(R) Xeon(R) Gold 6130 CPU @ 2.10GHz (skylake_avx512), Python 3.6.8
See https://gist.github.com/jfgrimm/3b7a02c7aa84d9e39171566a47712a18 for a full test report.

[jfgrimm]

lgtm

[jfgrimm]

Going in, thanks @Micket!