Update mgerrit activities

Update progaurd to keep classes used by reflection

Patch Set 2: include android-support-v4 library in Android.mk

Patch Set 3: Don't include authority in ROMControl manifest as it
causes INSTALL_FAILED_CONFLICTING_PROVIDER if users installs the
market edition alongside the embedded version (Still works as
as expected because authority is handled directly by mGerrit)

Change-Id: Ief2a65de4cb54a8554c73dddeec2b5916018dfb3
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>