veyron/security/agent: Added encryption to agent and option not
to encrypt.

* Password will only be requested when the PEM Block is not encrypted.
* Next step is to change the agent from a signer to a principal. Coming
  soon...

Change-Id: I811bb6af636d83243052465039192c7bfa307cc1
diff --git a/security/blessingstore_test.go b/security/blessingstore_test.go
index c7152bb..fd535d8 100644
--- a/security/blessingstore_test.go
+++ b/security/blessingstore_test.go
@@ -134,13 +134,10 @@
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(dir)
-	p, existed, err := NewPersistentPrincipal(dir)
+	p, err := CreatePersistentPrincipal(dir, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
-	if existed {
-		t.Errorf("%q already has a principal in it", dir)
-	}
 	tester := newStoreTester(p)
 	s := p.BlessingStore()
 
@@ -155,7 +152,7 @@
 	}
 
 	// Recreate the BlessingStore from the directory.
-	p2, _, err := NewPersistentPrincipal(dir)
+	p2, err := LoadPersistentPrincipal(dir, nil)
 	if err != nil {
 		t.Fatal(err)
 	}