IndexOutOfBoundsException in the PrintSpoolerService dump.

The dump code in PrintSpoolerService was relying on being
called only as a result of "adb shell dumpsys print" which
is apparently wrong. As a result the code was making wrong
assumption about the input arguments.

bug:11046234

Change-Id: Ie38f3cc5f17cac98b808fef6d6bbeaca22a62ef0
diff --git a/packages/PrintSpooler/src/com/android/printspooler/PrintSpoolerService.java b/packages/PrintSpooler/src/com/android/printspooler/PrintSpoolerService.java
index 87181f7..d1d71cd 100644
--- a/packages/PrintSpooler/src/com/android/printspooler/PrintSpoolerService.java
+++ b/packages/PrintSpooler/src/com/android/printspooler/PrintSpoolerService.java
@@ -236,7 +236,7 @@
     @Override
     protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
         synchronized (mLock) {
-            String prefix = args[0];
+            String prefix = (args.length > 0) ? args[0] : "";
             String tab = "  ";
 
             pw.append(prefix).append("print jobs:").println();