LU-12730 tests: sync file before checking LSOM

LU-12730 tests: sync file before checking LSOM

In sanity test_807, make sure files are synced before checking
LSOM info.

Test-Parameters: trivial envdefinitions=ONLY=807 testlist=sanity,sanity,sanity,sanity
Test-Parameters: envdefinitions=ONLY=807 testlist=sanity,sanity,sanity,sanity,sanity
Test-Parameters: envdefinitions=ONLY=807 testlist=sanity,sanity,sanity,sanity,sanity
Test-Parameters: envdefinitions=ONLY=807 testlist=sanity,sanity,sanity,sanity,sanity
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: Id6a452cc6b734d706581e70fed3770973ccce503
Reviewed-on: https://review.whamcloud.com/37146
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>