Check for null pkgList in fixSeInfoLocked()

Addresses:
03-08 17:26:18.550 11945 11945 E AndroidRuntime: *** FATAL EXCEPTION IN SYSTEM PROCESS: main
03-08 17:26:18.550 11945 11945 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference
03-08 17:26:18.550 11945 11945 E AndroidRuntime:        at com.android.server.pm.SharedUserSetting.fixSeInfoLocked(SharedUserSetting.java:129)

Which is triggered during an "adb sync"

Fixes: 74214574
Test: m -j && adb shell stop && adb remount && adb sync && adb shell start
Change-Id: I1908893fae05c70491f7cc776d0df49ec54f283b

services/core/java/com/android/server/pm/SharedUserSetting.java

@@ -125,6 +125,9 @@ public final class SharedUserSetting extends SettingBase {
      */
     public void fixSeInfoLocked() {
         final List<PackageParser.Package> pkgList = getPackages();
+        if (pkgList == null || pkgList.size() == 0) {
+            return;
+        }
 
         for (PackageParser.Package pkg : pkgList) {
             if (pkg.applicationInfo.targetSdkVersion < seInfoTargetSdkVersion) {