https://jira.hyperledger.org/browse/FAB-2022



This changes introduced by this CR
- Moves the block storage code from package
core/ledger/blkstorage to common/ledger/blkstorage

- Splits the ledger_interface.go so as to move common interfaces
and data type to common/ledger package

- Moves some of the util functions to common/ledger package

- Moves core/ledger/ordererledger package to orderer/ledger/fsledger
orderer folks can futher rename/refactor this as seems suitable to them

Change-Id: I759e16f00dc2ec9bb62196121083cf48eae76948
Signed-off-by: manish <manish.sethi@gmail.com>

https://jira.hyperledger.org/browse/FAB-1817



The golang tests in different packages are run in parallel
(unless controlled by special flag `-p=1`).
To avoid collision among tests of different packages,
use different folders that are used to store ledger contents.

Change-Id: I71a0d935a752fe26b8f309372db9210393bfcd49
Signed-off-by: manish <manish.sethi@gmail.com>

https://jira.hyperledger.org/browse/FAB-1664



This changeset:
- Renames package ledger/util/db to ledger/util/leveldbhelper
- Implements a leveldb provider
  (that enables using same leveldb instance as a multiple logical dbs)
  in util package for being able to reuse across statedb, index,
  and later for historydb
- Implements a provider as a single point of invocation
  for managing multiple block storage
- Uses a single leveldb instance for block storage index
- Makes the structures other than providers as private
  to their respective packages

Change-Id: I5f0b3b9aa8ef3ac1ccdce4f3c6fa6d842b5318c1
Signed-off-by: manish <manish.sethi@gmail.com>