Fix bash comparisons for grenade multinode switch
It seems, however variables are getting set with grenade
in native zuulv3 jobs, the environment variables are no
longer comparing as they once did in standard bash jobs.
What worked previously, was [ "$VAR" == 'value' ], however
when comparing the newer grenade node jobs we see things like
[[ subnode != \s\u\b\n\o\d\e ]] returning true when single
quotes are used.
Comparison in the logs to where double quotes were used for
functionally the same comparision, revealed proper processing
and execution as expected.
As such, changing our single quotes to double quotes where
For the record, I also quickly checked codesearch and it looks
like we were the only project to use single quotes for this