restorer: Sanitize verify errors

internal/restorer/restorer.go

@@ -351,6 +351,9 @@ func (res *Restorer) VerifyFiles(ctx context.Context, dst string) (int, error) {
 			for job := range work {
 				buf, err = res.verifyFile(job.path, job.node, buf)
 				if err != nil {
+					err = res.Error(job.path, err)
+				}
+				if err != nil || ctx.Err() != nil {
 					break
 				}
 				atomic.AddUint64(&nchecked, 1)

internal/restorer/restorer_test.go

@@ -844,5 +844,6 @@ func TestVerifyCancel(t *testing.T) {
 	nverified, err := res.VerifyFiles(ctx, tempdir)
 	rtest.Equals(t, 0, nverified)
 	rtest.Assert(t, err != nil, "nil error from VerifyFiles")
-	rtest.Equals(t, []error(nil), errs)
+	rtest.Equals(t, 1, len(errs))
+	rtest.Assert(t, strings.Contains(errs[0].Error(), "Invalid file size for"), "wrong error %q", errs[0].Error())
 }