Using prlimits is incompatible with passing arguments as a list:
oslo.concurrency ends up executing something like:
/opt/ironic-python-agent/bin/python3 -m oslo_concurrency.prlimit \
--as=2147483648 -- ['env', 'LC_ALL=C', 'LANG=C', 'qemu-img', 'info', \
'/tmp/cirros-0.6.2-x86_64-disk.img', '--output=json']
Which obviously fails. I don't understand how our CI has worked so far,
but the Metal3 BMO suite fails on this.
Change-Id: I46dbcb0f73bcbe09bb89b5c7195259570412698e
(cherry picked from commit fd8032b3601f79315eb683916fbd4a2a8d5cc74e)