Fire CB in Location off for requestCellInfoUpdate

When location is off, requestCellInfoUpdate needs to fire
a callback to fulfill its contract to always return something
to the caller and complete the transaction.

Bug: 132336748
Test: manual test with sl4a
Change-Id: I812ecfb8743838372ec43ae455e8fbd694f0391b
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index 9ccba80..e2d966a 100755
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -2136,6 +2136,11 @@
             case DENIED_HARD:
                 throw new SecurityException("Not allowed to access cell info");
             case DENIED_SOFT:
+                try {
+                    cb.onCellInfo(new ArrayList<CellInfo>());
+                } catch (RemoteException re) {
+                    // Drop without consequences
+                }
                 return;
         }