DPL: do not mask errors when generating workflows

[ktf]

No description provided.

[ktf]

@davidrohr @mfasDa can you check if this improves your building issues?

[ktf]

@knopers8 @Barthelemy this fails to generate the workflow configuration because the datasampling is not a real standalone workflow. Can we move to use o2_add_executable rather than o2_add_workflow?

[davidrohr]

@ktf : For reference: rebuilding with this PR, I am still getting the segfaults

[Mi Jan 13 09:52:06 2021] o2-testworkflow[19695]: segfault at 0 ip 0000000000000000 sp 00007ffeb315d5b8 error 14 in o2-testworkflows-aod-dummy-workflow[55a881839000+7000]
[Mi Jan 13 09:52:06 2021] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.

due to the zero function pointer, but at least now the build fails properly:

FAILED: stage/bin/o2-analysistutorial-associated-derived
2021-01-13@09:52:07:DEBUG:O2:O2:0: [ERROR] libO2FrameworkAnalysisSupport.so: cannot open shared object file: No such file or directory
2021-01-13@09:52:07:DEBUG:O2:O2:0: [ERROR] /usr/lib64/libuv.so.1: undefined symbol: dpl_plugin_callback

[knopers8]

@knopers8 @Barthelemy this fails to generate the workflow configuration because the datasampling is not a real standalone workflow. Can we move to use o2_add_executable rather than o2_add_workflow?

OK, sure. I'll post a fix soon.

[davidrohr]

rebased to dev, since the dependency is apparently required for the build order.