Remove ExtendedCommitSig.ForBlock helper

Signed-off-by: Thane Thomson <connect@thanethomson.com>

types/block.go

@@ -737,11 +737,6 @@ func NewExtendedCommitSigAbsent() ExtendedCommitSig {
 	return ExtendedCommitSig{BlockIDFlag: BlockIDFlagAbsent}
 }
 
-// ForBlock returns true if ExtendedCommitSig is for the block.
-func (ecs ExtendedCommitSig) ForBlock() bool {
-	return ecs.BlockIDFlag == BlockIDFlagCommit
-}
-
 // Absent returns true if ExtendedCommitSig is absent.
 func (ecs ExtendedCommitSig) Absent() bool {
 	// TODO(sergio): What about BlockIDFlagNil?

types/vote_set.go

@@ -628,7 +628,7 @@ func (voteSet *VoteSet) MakeExtendedCommit() *ExtendedCommit {
 	for i, v := range voteSet.votes {
 		sig := v.ExtendedCommitSig()
 		// if block ID exists but doesn't match, exclude sig
-		if sig.ForBlock() && !v.BlockID.Equals(*voteSet.maj23) {
+		if sig.BlockIDFlag == BlockIDFlagCommit && !v.BlockID.Equals(*voteSet.maj23) {
 			sig = NewExtendedCommitSigAbsent()
 		}