[FAB-4301] core.yaml update

updated the ledger/history section to indicate that
goleveldb is always used for history regardless if
you are using CouchDB or anything else for the state

[ci-skip]

Change-Id: Icb0907e7ae867c9710d370b7244f8c85c63f0fd9
Signed-off-by: Mark Parzygnat <markparz@us.ibm.com>

sampleconfig/core.yaml

@@ -379,5 +379,7 @@ ledger:
 
   history:
     # enableHistoryDatabase - options are true or false
-    # Indicates if the history of key updates should be stored in goleveldb
+    # Indicates if the history of key updates should be stored.
+    # All history 'index' will be stored in goleveldb, regardless if using
+    # CouchDB or alternate database for the state.
     enableHistoryDatabase: true