Return false in flamegraph.is_enabled in case the common_module is None

[nastra]

is_enabled() is accessed in https://github.com/datastax/cstar_perf/blob/master/tool/cstar_perf/tool/fab_common.py#L442-442 and common_module wasn't initialized yet. Maybe an alternate fix might be to properly call https://github.com/datastax/cstar_perf/blob/master/tool/cstar_perf/tool/fab_flamegraph.py#L20-20 before it is used in https://github.com/datastax/cstar_perf/blob/master/tool/cstar_perf/tool/fab_common.py#L442-442 ?

[aboudreault]

@nastra What test are you doing to get this not initialized? I only added the setup in stress_compare though, so It might need to be added somewhere else

[nastra]

I'm doing cstar_perf_bootstrap -v 4.8.1 where I set up DSE

[aboudreault]

ah, right. I think it might be useful for future uses to add the flamegraph setup for the boostrap operation.

[aboudreault]

Fixed in latest master. Thanks!