multi: use witnessScript everywhere instead of redeemScript

This commit consists of a mass variable renaming to call the pkScript being executed for segwit outputs the `witnessScript` instead of `redeemScript`. The latter naming convention is generally considered to be reserved for the context of BIP 16 execution. With segwit to be deployed soon, we should be using the correct terminology uniformly through the codebase. 

In addition some minor typos throughout the codebase has been fixed.

channeldb/channel.go

@@ -127,7 +127,7 @@ type OpenChannel struct {
 
 	OurMultiSigKey      *btcec.PublicKey
 	TheirMultiSigKey    *btcec.PublicKey
-	FundingRedeemScript []byte
+	FundingWitnessScript []byte
 
 	// In blocks
 	LocalCsvDelay  uint32
@@ -1095,7 +1095,7 @@ func putChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel) error
 		return err
 	}
 
-	if err := wire.WriteVarBytes(&b, 0, channel.FundingRedeemScript[:]); err != nil {
+	if err := wire.WriteVarBytes(&b, 0, channel.FundingWitnessScript[:]); err != nil {
 		return err
 	}
 
@@ -1151,7 +1151,7 @@ func fetchChanFundingInfo(nodeChanBucket *bolt.Bucket, channel *OpenChannel) err
 		return err
 	}
 
-	channel.FundingRedeemScript, err = wire.ReadVarBytes(infoBytes, 0, 520, "")
+	channel.FundingWitnessScript, err = wire.ReadVarBytes(infoBytes, 0, 520, "")
 	if err != nil {
 		return err
 	}

channeldb/channel_test.go

@@ -148,7 +148,7 @@ func createTestChannelState(cdb *DB) (*OpenChannel, error) {
 		FundingOutpoint:            testOutpoint,
 		OurMultiSigKey:             privKey.PubKey(),
 		TheirMultiSigKey:           privKey.PubKey(),
-		FundingRedeemScript:        script,
+		FundingWitnessScript:        script,
 		TheirCurrentRevocation:     privKey.PubKey(),
 		TheirCurrentRevocationHash: key,
 		OurDeliveryScript:          script,
@@ -257,7 +257,7 @@ func TestOpenChannelPutGetDelete(t *testing.T) {
 		newState.TheirMultiSigKey.SerializeCompressed()) {
 		t.Fatalf("their multisig key doesn't match")
 	}
-	if !bytes.Equal(state.FundingRedeemScript, newState.FundingRedeemScript) {
+	if !bytes.Equal(state.FundingWitnessScript, newState.FundingWitnessScript) {
 		t.Fatalf("redeem script doesn't match")
 	}