Further Credentials-related clean-up

Additional clean-up work related to removal of screenlock dependency
from the credentials installation flow:
* Move the CredentialStorage class to security/ so that Enterprise team
  owners could review changes to it.
* Remove the ConfigureKeyGuardDialog class as it is no longer used.
* Remove attempt to unlock KeyStore from VPN settings.
* Remove intents that will no longer be sent from the manifest.

Bug: 120901345
Test: m -j RunSettingsRoboTests
Test: Manual with CtsVerifier
Change-Id: Ia708ede3366892d74c148f3712a63858d5ab53b7

src/com/android/settings/vpn2/ConfigDialogFragment.java

@@ -56,8 +56,6 @@ public class ConfigDialogFragment extends InstrumentedDialogFragment implements
             ServiceManager.getService(Context.CONNECTIVITY_SERVICE));
     private Context mContext;
 
-    private boolean mUnlocking = false;
-
 
     @Override
     public int getMetricsCategory() {
@@ -84,27 +82,6 @@ public class ConfigDialogFragment extends InstrumentedDialogFragment implements
         mContext = context;
     }
 
-    @Override
-    public void onResume() {
-        super.onResume();
-
-        // Check KeyStore here, so others do not need to deal with it.
-        if (!KeyStore.getInstance().isUnlocked()) {
-            if (!mUnlocking) {
-                // Let us unlock KeyStore. See you later!
-                Credentials.getInstance().unlock(mContext);
-            } else {
-                // We already tried, but it is still not working!
-                dismiss();
-            }
-            mUnlocking = !mUnlocking;
-            return;
-        }
-
-        // Now KeyStore is always unlocked. Reset the flag.
-        mUnlocking = false;
-    }
-
     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState) {
         Bundle args = getArguments();