multi: add new NoRevLogAmtData config option

In this commit, a new `--db.no-rev-log-amt-data` flag is added. The
config option is passed though to everywhere that it will be used. Note
that it is still a no-op in this commit. An upcoming commit will make
use of the flag.

channeldb/options.go

@@ -64,6 +64,10 @@ type Options struct {
 	// applications that use the channeldb package as a library.
 	NoMigration bool
 
+	// NoRevLogAmtData when set to true, indicates that amount data should
+	// not be stored in the revocation log.
+	NoRevLogAmtData bool
+
 	// clock is the time source used by the database.
 	clock clock.Clock
 
@@ -130,6 +134,14 @@ func OptionSetUseGraphCache(use bool) OptionModifier {
 	}
 }
 
+// OptionNoRevLogAmtData sets the NoRevLogAmtData option to the given value. If
+// it is set to true then amount data will not be stored in the revocation log.
+func OptionNoRevLogAmtData(noAmtData bool) OptionModifier {
+	return func(o *Options) {
+		o.NoRevLogAmtData = noAmtData
+	}
+}
+
 // OptionSetSyncFreelist allows the database to sync its freelist.
 func OptionSetSyncFreelist(b bool) OptionModifier {
 	return func(o *Options) {