handle templating correctly in CMakeMake when playing with configopts

[mboisson]

fixes #2881

[Flamefire]

Looks good to me now but I was looking into another approach: Not modifying configopts at all: #2885

I noticed another issue with #2514: When iterating the values from a previous iteration will still be in configopts. So I see a much larger issue with the implementation of the iteration: Shouldn't the iterations be independent of each other? EasyBlocks may rightfully modify the self.cfg values to keep them across steps but that means the next iteration does not start with the same values as it should.

Until that is fixed in framework #2885 stops modifying configopts as it was the case before #2514

[boegel]

lgtm

[boegel]

Test report by @boegel

Overview of tested easyconfigs (in order)

• SUCCESS MetaBAT-2.14-gompi-2019a.eb

Build succeeded for 1 out of 1 (1 easyconfigs in total)
node3170.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/0228bca735afebd25c801a3242cdb434 for a full test report.