[vpython] Verify environment, named installs.

vpython/application/subcommand_verify.go

Index: vpython/application/subcommand_verify.go
diff --git a/vpython/application/subcommand_verify.go b/vpython/application/subcommand_verify.go
index 95762377f1746947a984d2d5d17cac4709868db7..b9c3e43abe278c302a94f8fbe4fc85594c428e78 100644
--- a/vpython/application/subcommand_verify.go
+++ b/vpython/application/subcommand_verify.go
@@ -42,7 +42,10 @@ func (cr *verifyCommandRun) Run(app subcommands.Application, args []string, env
 		if err := a.opts.ResolveSpec(c); err != nil {
 			return errors.Annotate(err).Reason("failed to resolve specification").Err()
 		}
-		if err := spec.Normalize(a.opts.EnvConfig.Spec, &a.opts.EnvConfig.Package); err != nil {
+		if a.opts.EnvConfig.Spec.Virtualenv == nil {
+			a.opts.EnvConfig.Spec.Virtualenv = &a.opts.EnvConfig.Package
+		}
+		if err := spec.NormalizeSpec(a.opts.EnvConfig.Spec); err != nil {
 			return errors.Annotate(err).Reason("failed to normalize specification").Err()
 		}
 		s := a.opts.EnvConfig.Spec