Integrate VPN with new keystore and misc fixes.

* Changes
  + Pass intent to keystore when needed and hooks to resume from it.
  + Generate random, unique ID for profile instead of base64 from its
    name.
  + Add VPN to "Wirless controls" description.
  + Add credential storage to "Security & location" description.
  + More hints to set password and unlock dialogs in credential storage
    settings for actions that come from other processes.
  + Sort VPN profiles according to the names.
  + Replace Keystore with CertTool in L2tpIpsecEditor

src/com/android/settings/vpn/VpnProfileEditor.java

@@ -91,13 +91,6 @@ class VpnProfileEditor {
                 : validate(mServerName, R.string.vpn_vpn_server));
     }
 
-    /**
-     * Saves the secrets in this profile.
-     * @param originalProfileName the original profile name
-     */
-    public void saveSecrets(String originalProfileName) {
-    }
-
     /**
      * Creates a preference for users to input domain suffices.
      */