Implement SAML endpoints for APIv4 (#5671)

* Implement SAML endpoints for APIv4

* Fix unit test

* Only disable encryption when removing puplic/private certs

model/saml_test.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestSamlCertificateStatusJson(t *testing.T) {
+	status := &SamlCertificateStatus{IdpCertificateFile: true, PrivateKeyFile: true, PublicCertificateFile: true}
+	json := status.ToJson()
+	rstatus := SamlCertificateStatusFromJson(strings.NewReader(json))
+
+	if status.IdpCertificateFile != rstatus.IdpCertificateFile {
+		t.Fatal("IdpCertificateFile do not match")
+	}
+
+	rstatus = SamlCertificateStatusFromJson(strings.NewReader("junk"))
+	if rstatus != nil {
+		t.Fatal("should be nil")
+	}
+}