LU-3208 tests: Fix typo in replay-single/70b

LU-3208 tests: Fix typo in replay-single/70b

Missing space in if statement, caused syntax error:

	replay-single.sh: line 1912 [: missing `]`

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Change-Id: I2543f9b8fe41153d6109a64d2619a8443e700d9d
Reviewed-on: http://review.whamcloud.com/6131
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>