After the ae324984cb steady
checkpoint(s) could be created automatically while reserve a
pages for deletion from freeDB.
In other words, some (beginning of list) of modify-ops were
"unexpectedly" synced to disk, despite of the no-sync closing
of DB by the mtest1 - therefore testcase could fail.
Now required rollback at least one of transactions after the
last explicit sync, but not all of ones.
Change-Id: I6ca6dba8a62a30f12f370fa91325efdf4fe35772
