health: Add CAP_WAKE_ALARM to service via init

platform/interfaces/health/2.0/default/healthd_common.cpp wants to use
timerfd_create() to register a wakealarm.

To use the timerfd_create() syscall with CLOCK_BOOTTIME_ALARM,
CAP_WAKE_ALARM is needed.

Since the .rc file for android.hardware.health@2.0 is shipped here in
system/core, update it here.

Signed-off-by: Felix <google@ix5.org>
Change-Id: I6cd5701b6e5cac37eb021d894251a3a9dc590b95
(cherry picked from commit fb559554)