Fix missing summary for CheckBoxPreference

- "summaryOn" and "summaryOff" were parsed but we were missing
also "summary"

Repro case: search for "adt" (from Developer options)

Change-Id: Ifa829ec6c6f86cb426432f716c2d28df8550f9ea
diff --git a/src/com/android/settings/search/Index.java b/src/com/android/settings/search/Index.java
index 6f91981..4f5aa2c 100644
--- a/src/com/android/settings/search/Index.java
+++ b/src/com/android/settings/search/Index.java
@@ -761,8 +761,12 @@
                             keywords, intentAction, intentTargetPackage, intentTargetClass,
                             true, key);
                 } else {
-                    final String summaryOn = getDataSummaryOn(context, attrs);
-                    final String summaryOff = getDataSummaryOff(context, attrs);
+                    String summaryOn = getDataSummaryOn(context, attrs);
+                    String summaryOff = getDataSummaryOff(context, attrs);
+
+                    if (TextUtils.isEmpty(summaryOn) && TextUtils.isEmpty(summaryOff)) {
+                        summaryOn = getDataSummary(context, attrs);
+                    }
 
                     updateOneRowWithFilteredData(database, localeStr, title, summaryOn, summaryOff,
                             null, fragmentName, screenTitle, iconResId, rank,