Fix static AID prefix registration.

Bug: 16517161
Change-Id: Ibaddf8720907f1d28d44231d927f538628bbf9d0
diff --git a/core/java/android/nfc/cardemulation/ApduServiceInfo.java b/core/java/android/nfc/cardemulation/ApduServiceInfo.java
index 646134e..3811375 100644
--- a/core/java/android/nfc/cardemulation/ApduServiceInfo.java
+++ b/core/java/android/nfc/cardemulation/ApduServiceInfo.java
@@ -231,7 +231,7 @@
                     String aid = a.getString(com.android.internal.R.styleable.AidFilter_name).
                             toUpperCase();
                     // Add wildcard char to indicate prefix
-                    aid.concat("*");
+                    aid = aid.concat("*");
                     if (CardEmulation.isValidAid(aid) && !currentGroup.aids.contains(aid)) {
                         currentGroup.aids.add(aid);
                     } else {