Don't NPE when no security message is provided.

CTS tests that all services which implement a dump call
checks for the android.permission.DUMP permission.

Assume that a security exception which contains no message
represents a properly protected dump interface.

Bug: 12477602
Change-Id: I98ab2c74443161f9229900b9ac0e5124f687d99b
(cherry picked from commit 1fedb198fa3acb88a143deef5c29667e820186a5)
1 file changed