Fixes issue #1232 (#1233)

* Fixes issue #1232

* Adding/updating test cases

* Updating as per comments

* Use tx instead of db in GetModifiedAccounts and clean up a bit

* option to specify LMDB map size for cmd/integration commands (#1238)

* Add lmdb.mapSize to integration

* Make lmdb.mapSize effective

* Use mapSize for first opening

* Fix for cobra

* Extend lmdb.mapSize for all commands

* Fix lint

* Fixes issue #1232

* Adding/updating test cases

* Updating as per comments

Co-authored-by: ledgerwatch <akhounov@gmail.com>