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