Call preference.setEnabled only after updating disabledByAdmin state.

We check the value of disabledByAdmin state in setEnabled, so update it
first before calling setEnabled.

Bug: 27642236
Change-Id: Ie6c805b85a3afb87ffdaad0b80dbadc172b62d49
diff --git a/packages/SettingsLib/src/com/android/settingslib/RestrictedPreferenceHelper.java b/packages/SettingsLib/src/com/android/settingslib/RestrictedPreferenceHelper.java
index 47023c1..d0aba22 100644
--- a/packages/SettingsLib/src/com/android/settingslib/RestrictedPreferenceHelper.java
+++ b/packages/SettingsLib/src/com/android/settingslib/RestrictedPreferenceHelper.java
@@ -146,12 +146,13 @@
     public boolean setDisabledByAdmin(EnforcedAdmin admin) {
         final boolean disabled = (admin != null ? true : false);
         mEnforcedAdmin = admin;
-        mPreference.setEnabled(!disabled);
+        boolean changed = false;
         if (mDisabledByAdmin != disabled) {
             mDisabledByAdmin = disabled;
-            return true;
+            changed = true;
         }
-        return false;
+        mPreference.setEnabled(!disabled);
+        return changed;
     }
 
     public boolean isDisabledByAdmin() {