LU-2414 tests: fix job # substitution in replay_barrier

LU-2414 tests: fix job # substitution in replay_barrier

The extra % in front of ${!svc} can cause erronious substitution by
bash, as in If ${!svc} resolves to something like nlc then the %n
becomes job number 0 so the filesystem is 0lc and that fails.

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Change-Id: I4a0b0db86e960a33dab95b2e7ca4aed7fce4a55d
Reviewed-on: http://review.whamcloud.com/4725
Tested-by: Hudson
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>