Allow multiuser use of keystore

Since keystore has been refactored to let muliple users use it
simultaneously, we can remove all the restrictions put into place to
prevent it.

(cherry picked from commit cc48b0104e)

Bug: 7249554
Change-Id: I419474151380c29e49e50451befbbdf3af65b175

src/com/android/settings/CredentialStorage.java

@@ -25,7 +25,6 @@ import android.content.res.Resources;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.os.RemoteException;
-import android.os.UserHandle;
 import android.security.Credentials;
 import android.security.KeyChain.KeyChainConnection;
 import android.security.KeyChain;
@@ -109,12 +108,6 @@ public final class CredentialStorage extends Activity {
     protected void onResume() {
         super.onResume();
 
-        if (UserHandle.myUserId() != UserHandle.USER_OWNER) {
-            Log.i(TAG, "Cannot install to CredentialStorage as non-primary user");
-            finish();
-            return;
-        }
-
         Intent intent = getIntent();
         String action = intent.getAction();
 

src/com/android/settings/SecuritySettings.java

@@ -234,8 +234,7 @@ public class SecuritySettings extends SettingsPreferenceFragment
         // Show password
         mShowPassword = (CheckBoxPreference) root.findPreference(KEY_SHOW_PASSWORD);
 
-        // Credential storage, only for primary user
-        if (mIsPrimary) {
+        // Credential storage
         mKeyStore = KeyStore.getInstance();
         Preference credentialStorageType = root.findPreference(KEY_CREDENTIAL_STORAGE_TYPE);
 
@@ -245,10 +244,8 @@ public class SecuritySettings extends SettingsPreferenceFragment
         credentialStorageType.setSummary(storageSummaryRes);
 
         mResetCredentials = root.findPreference(KEY_RESET_CREDENTIALS);
-        } else {
-            removePreference(KEY_CREDENTIALS_MANAGER);
-        }
 
+        // Application install
         PreferenceGroup deviceAdminCategory= (PreferenceGroup)
                 root.findPreference(KEY_DEVICE_ADMIN_CATEGORY);
         mToggleAppInstallation = (CheckBoxPreference) findPreference(