make com.android.mediadrm.signer available on all devices
make com.android.mediadrm.signer available on all devices

bug: 16978496
Change-Id: I238e6fa7fc4e588f52f86130a2721c391959a94a

xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build