Part 3 of ledger servicebility improvement:
Update common/ledger to use error handling framework

Change-Id: I86383b404941c5f922fa2f26ca71af4d91351d4c
Signed-off-by: Wenjian Qiao <wenjianq@gmail.com>

This CR
   - Adds unit tests to enhance the code coverage of the package
   fabric/common/ledger/blkstorage/fsblkstorage
   - Removes an unused function
   - fixes a few comments/debug message

Change-Id: Iab0cbdc6fe8295aa73a0f8a08390ba0f83f24204
Signed-off-by: manish <manish.sethi@gmail.com>

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-903



The bug was caused by an assumption in the code -
that the minimum size of a block would be 8 bytes.
This assumption is broken during testing when security is off
and a block does not include any transaction

Change-Id: Ib48ea3da2a661fbd8e4122573bac938c8b35f3d1
Signed-off-by: manish <manish.sethi@gmail.com>

Raw ledger provides basic functionality for storing and
retrieving blocks. This is intended to be used by an orderer service
https://jira.hyperledger.org/browse/FAB-56



Change-Id: I3fb733f5be53b6f630c20554ba4e362540b8f55a
Signed-off-by: manish <manish.sethi@gmail.com>

FAB-853

Ledger is removed from
   . core/peer/peer.go
   . core/rest/api.go

Ledger package itself is removed. "ledgernext" is
replaced with "ledger".

Change-Id: Ie7dfbd9bf94afa0031aef759fc46929e4fb3b400
Signed-off-by: Srinivasan Muralidharan <muralisr@us.ibm.com>

This commit adds the functionality of checkpointing block index progress
and sync-ing (updating) the index during start of the block storage system

Change-Id: Ib1a325add455bce47e510ccfc7af052db51117e6
Signed-off-by: manish <manish.sethi@gmail.com>

This commit allows a block stream consumer read across multiple files.

Change-Id: I1bd053e8d022bf1daf01f61f9e3e1ae1629e334b
Signed-off-by: manish <manish.sethi@gmail.com>