Add summary for 0 fingerprint settings preference

This allows the fingerprint summary to be shown when there
are no fingerprints.

Fixes bug 24172006

Change-Id: I9dd266013ac74da74f1dd397cbe0e50acf5d1262

src/com/android/settings/SecuritySettings.java

@@ -361,6 +361,8 @@ public class SecuritySettings extends SettingsPreferenceFragment
                     fingerprintCount, fingerprintCount));
             clazz = FingerprintSettings.class.getName();
         } else {
+            fingerprintPreference.setSummary(
+                    R.string.security_settings_fingerprint_preference_summary_none);
             clazz = FingerprintEnrollIntroduction.class.getName();
         }
         intent.setClassName("com.android.settings", clazz);