Fix QuickContact is finished when cancelling link action

If no contact to be linked selected, null intent is returned to
QuickContact Activity. Should just return instead of processing the
intent.

Bug: 32024874

Test: Manually tested when opening QuickContact from main contacts
list, label view, and account view, following repro steps previous
QuickContact view shows.

Change-Id: Id89413ade3f7dac227c160ae5ab8e96bc1e48960
diff --git a/src/com/android/contacts/quickcontact/QuickContactActivity.java b/src/com/android/contacts/quickcontact/QuickContactActivity.java
index 52c66d5..f8d7436 100644
--- a/src/com/android/contacts/quickcontact/QuickContactActivity.java
+++ b/src/com/android/contacts/quickcontact/QuickContactActivity.java
@@ -908,7 +908,7 @@
         } else if (requestCode == REQUEST_CODE_JOIN) {
             // Ignore failed requests
             if (resultCode != Activity.RESULT_OK) {
-                processIntent(data);
+                return;
             }
             if (data != null) {
                 joinAggregate(ContentUris.parseId(data.getData()));