bug fix possible NPE while startProcessLocked()

In case, process doesn't create well while startingProcessLocked().
There is possibility to make NPE.
Setting app's crash handler needs to be assigned after null check routine.

Change-Id: I67fb6427f72d93f79fed36eb44c47d37eafdac31
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 6823119..fde9049 100755
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -2808,12 +2808,12 @@
         if (app == null) {
             checkTime(startTime, "startProcess: creating new process record");
             app = newProcessRecordLocked(info, processName, isolated, isolatedUid);
-            app.crashHandler = crashHandler;
             if (app == null) {
                 Slog.w(TAG, "Failed making new process record for "
                         + processName + "/" + info.uid + " isolated=" + isolated);
                 return null;
             }
+            app.crashHandler = crashHandler;
             mProcessNames.put(processName, app.uid, app);
             if (isolated) {
                 mIsolatedProcesses.put(app.uid, app);