Resolve certificate references in ONC by PEM.

chromeos/test/data/network/valid_l2tpipsec_clientcert.onc

Index: chromeos/test/data/network/valid_l2tpipsec_clientcert.onc
diff --git a/chromeos/test/data/network/valid_l2tpipsec_clientcert.onc b/chromeos/test/data/network/valid_l2tpipsec_clientcert.onc
deleted file mode 100644
index 6f20b18a9c24f78d69e221b2ba7284f3a2919856..0000000000000000000000000000000000000000
--- a/chromeos/test/data/network/valid_l2tpipsec_clientcert.onc
+++ /dev/null
@@ -1,31 +0,0 @@
-{ "GUID": "guid",
-  "Type": "VPN",
-  "Name": "MyL2TPVPN",
-  "VPN": {
-      "Type": "L2TP-IPsec",
-      "Host": "some.host.org",
-      "IPsec": {
-          "AuthenticationType": "Cert",
-          "ClientCertType": "Pattern",
-          "ClientCertPattern": {
-              "EnrollmentURI": [ "my.enrollment.url" ],
-              "IssuerCARef": [
-                  "def",
-                  "abc"
-              ],
-              "Issuer": {
-                  "CommonName": "common_name",
-                  "Locality": "locality",
-                  "Organization": "organization",
-                  "OrganizationalUnit": "unit"
-              }
-          },
-          "IKEVersion": 1,
-          "SaveCredentials": true
-      },
-      "L2TP": {
-          "Username": "some username",
-          "Password": "some password"
-      }
-  }
-}