Remove unnecessary proguard flags

These are now exported from these libraries automatically.

Test: m DeskClock
Change-Id: Iff6df75f4cfeb01b16b4b823092b4a821ed52900
Merged-In: Iff6df75f4cfeb01b16b4b823092b4a821ed52900
(cherry picked from commit 680cdff8b9a9405babb22131f918e72af01496ef)
1 file changed