Fix crash if package setting is not populated yet

Bug: 17388687
Change-Id: I441ec37396a3b725a79b933a182c63fbe52d5646
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index 5639234..0600ef8 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -13018,6 +13018,9 @@
         Iterator<PackageSetting> psit = mSettings.mPackages.values().iterator();
         while (psit.hasNext()) {
             PackageSetting ps = psit.next();
+            if (ps.pkg == null) {
+                continue;
+            }
             final String packageName = ps.pkg.packageName;
             // Skip over if system app
             if ((ps.pkgFlags & ApplicationInfo.FLAG_SYSTEM) != 0) {