istanbul config needs to be updated
istanbul config needs to be updated

FAB-1995
reference to "hfc" to be updated with "fabric-client" so that
istanbul line coverage reports can be accurately generated

Change-Id: I209b3b850b07a4d836b65ee6f5e540e5aab9eb46
Signed-off-by: Jim Zhang <6775950e159d0bc2e58935ca2201ba88526dddf0@us.ibm.com>

ratnakar-asara/fabric-sdk-node,adityachap/fabric-sdk-node,adityachap/fabric-sdk-node,ratnakar-asara/fabric-sdk-node,ratnakar-asara/fabric-sdk-node,ratnakar-asara/fabric-sdk-node