LU-15626 tests: Fix "error" reported by shellcheck for recovery-double-scale

LU-15626 tests: Fix "error" reported by shellcheck for recovery-double-scale

This patch fixes "error" issues reported by shellcheck
for file lustre/tests/recovery-double-scale. This patch
also moves spaces to tabs.

Test-Parameters: trivial clientcount=6 mdtcount=2 mdscount=2 osscount=2 austeroptions=-R failover=true iscsi=1 env=FAILOVER_PERIOD=180 testlist=recovery-double-scale env=SLOW=yes
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: Iddb505f717bc87dd314d7bd988ba5db2271d8125
Reviewed-on: https://review.whamcloud.com/46825
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>