Move blobref.ParseMulti to its sole caller, with error checking.

Change-Id: I6351591497879ea5a113bc8e8414b751b3d1c812

cmd/camput/remove.go

@@ -44,5 +44,13 @@ func (c *removeCmd) RunCommand(args []string) error {
 	if len(args) == 0 {
 		return cmdmain.ErrUsage
 	}
-	return getUploader().RemoveBlobs(blobref.ParseMulti(args))
+	refs := make([]*blobref.BlobRef, 0, len(args))
+	for _, s := range args {
+		br := blobref.Parse(s)
+		if br == nil {
+			return fmt.Errorf("Invalid blobref %q", s)
+		}
+		refs = append(refs, br)
+	}
+	return getUploader().RemoveBlobs(refs)
 }

pkg/blobref/blobref.go

@@ -240,12 +240,3 @@ func MustParse(ref string) *BlobRef {
 	}
 	return br
 }
-
-// May return nil in list positions where the blobref could not be parsed.
-func ParseMulti(refs []string) (parsed []*BlobRef) {
-	parsed = make([]*BlobRef, 0, len(refs))
-	for _, ref := range refs {
-		parsed = append(parsed, Parse(ref))
-	}
-	return
-}