Fix a bigInt cmp bug

staking/types/delegation.go

@@ -13,6 +13,11 @@ var (
 	errInvalidAmount       = errors.New("Invalid amount, must be positive")
 )
 
+const (
+	// The number of epochs a undelegated token needs to be before it's released to the delegator's balance
+	LockPeriodInEpoch = 14
+)
+
 // Delegation represents the bond with tokens held by an account. It is
 // owned by one delegator, and is associated with the voting power of one
 // validator.
@@ -99,7 +104,7 @@ func (d *Delegation) RemoveUnlockedUndelegations(curEpoch *big.Int) *big.Int {
 	totalWithdraw := big.NewInt(0)
 	count := 0
 	for j := range d.Entries {
-		if curEpoch.Cmp(d.Entries[j].Epoch) > 14 { // need to wait at least 14 epochs to withdraw;
+		if big.NewInt(0).Sub(curEpoch, d.Entries[j].Epoch).Int64() > LockPeriodInEpoch { // need to wait at least 14 epochs to withdraw;
 			totalWithdraw.Add(totalWithdraw, d.Entries[j].Amount)
 			count++
 		} else {