[FAB-10093] Increase UT coverage ledger/ledgerstorage
[FAB-10093] Increase UT coverage ledger/ledgerstorage

This CR adds more UTs and increase the code coverage by UTs
from 72% to 87%

Change-Id: I15d3e692e4449ce80b894fe8da4acfd42073510b
Signed-off-by: manish <a9d79eea65b0c2019f8af02c53bb35240dcbd527@gmail.com>

manish-sethi/fabric-sidedb,binhn/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric,manish-sethi/fabric,hyperledger/fabric,manish-sethi/fabric-sidedb,binhn/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,muralisrini/fabric,stemlending/fabric,binhn/fabric,xixuejia/fabric,hyperledger/fabric,xixuejia/fabric,stemlending/fabric,jimthematrix/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric-sidedb,xixuejia/fabric,jimthematrix/fabric