Fix quoting in zuul for tempest plugins

Something has changed and the quoting used in the zuul jobs
configuration no longer works[1]. This patch removes the excess
quoting.

[1] http://logs.openstack.org/61/665861/6/check/ \
    octavia-v2-dsvm-noop-api/dac4dba/job-output.txt.gz \
    #_2019-06-26_14_13_23_428457

Change-Id: Ib5f55a8885e8f5d39af9f464b2bb71d4bde599f0
1 file changed