Remove signature generation from UpdateTestApp

The need for a signature was removed in internal changes for the
M release. Instead, a permission is required.

Related commits:
12964bf5dd36d13fc25efef7c7175a677f9490a5
ef3d6079a55f559191c90d15e3f30a72b576c499

Bug: 19941636
(cherry picked from commit ba148e2de81badc77ad21daca18996d0766e412e)

Change-Id: Ie107b344b4e60cd4d71fe78a87d2260405d94c3a
2 files changed