VpnSettings: use USER_PRIVATE_KEY to list user certificates.

Change-Id: Iba547331d00ddfe24dd5eda3a9ee70c9d17969d0
diff --git a/src/com/android/settings/vpn2/VpnDialog.java b/src/com/android/settings/vpn2/VpnDialog.java
index 6703187..ca85d99 100644
--- a/src/com/android/settings/vpn2/VpnDialog.java
+++ b/src/com/android/settings/vpn2/VpnDialog.java
@@ -113,7 +113,7 @@
         mL2tpSecret.setText(mProfile.l2tpSecret);
         mIpsecIdentifier.setText(mProfile.ipsecIdentifier);
         mIpsecSecret.setText(mProfile.ipsecSecret);
-        loadCertificates(mIpsecUserCert, Credentials.USER_CERTIFICATE,
+        loadCertificates(mIpsecUserCert, Credentials.USER_PRIVATE_KEY,
                 0, mProfile.ipsecUserCert);
         loadCertificates(mIpsecCaCert, Credentials.CA_CERTIFICATE,
                 R.string.vpn_no_ca_cert, mProfile.ipsecCaCert);