Fix ArrayBounds exception in joinContacts

Fix ArrayBounds exception: detect when there are no RawContacts to join.

Bug:7970480
Change-Id: I2cee8bbb0c712f52bf616a227595d2ec94ec7bdb
diff --git a/src/com/android/contacts/ContactSaveService.java b/src/com/android/contacts/ContactSaveService.java
index d87a1a0..7c8782f 100644
--- a/src/com/android/contacts/ContactSaveService.java
+++ b/src/com/android/contacts/ContactSaveService.java
@@ -1013,6 +1013,9 @@
         long rawContactIds[];
         long verifiedNameRawContactId = -1;
         try {
+            if (c.getCount() == 0) {
+                return;
+            }
             int maxDisplayNameSource = -1;
             rawContactIds = new long[c.getCount()];
             for (int i = 0; i < rawContactIds.length; i++) {