test open in-memory snapshot post rollback
test open in-memory snapshot post rollback

set 3 items + commit, set 2 more + commit again.
rollback to 3 then open in-mem snapshot on kv and create iterator expecting
3 items to be returned

Change-Id: Iaebf42b2171d9e3a5155007140a96f0f8e88229b

hisundar/forestdb,jinxuan/forestdb,hisundar/forestdb,sushmaad/forestdb,yyangpan/forestdb,joliss/forestdb,zhaog/forestdb,yyangpan/forestdb,couchbase/forestdb,couchbase/forestdb,jinxuan/forestdb,wurikiji/forestdb,zhaog/forestdb,wurikiji/forestdb,sushmaad/forestdb,joliss/forestdb