cmd/go/internal/modfetch: remove redundant check for semver

The function semver.IsValid(vers) would check whether vers has a "v" prefix.

Change-Id: I9d8381af6bd04d228846701b3f910ec5add61ae6
Reviewed-on: https://go-review.googlesource.com/118936
Run-TryBot: Baokun Lee <nototon@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

vendor/cmd/go/internal/modfetch/query.go

diff --git a/vendor/cmd/go/internal/modfetch/query.go b/vendor/cmd/go/internal/modfetch/query.go
index 5587890..b5b8813 100644
--- a/vendor/cmd/go/internal/modfetch/query.go
+++ b/vendor/cmd/go/internal/modfetch/query.go
@@ -28,7 +28,7 @@
 // result to revisions on a particular branch name.
 //
 func Query(path, vers string, allowed func(module.Version) bool) (*RevInfo, error) {
-	if strings.HasPrefix(vers, "v") && semver.IsValid(vers) {
+	if semver.IsValid(vers) {
 		// TODO: This turns query for "v2" into Stat "v2.0.0",
 		// but probably it should allow checking for a branch named "v2".
 		vers = semver.Canonical(vers)