selinux: Fix healthd's access to /dev nodes

Our healthd's support for power-on alarms adds some steps that imply
reading files its user doesn't own. Let it.

Change-Id: I3d4735aaab8fbec7acc460f812bc21f1dfa516ab
diff --git a/sepolicy/healthd.te b/sepolicy/healthd.te
new file mode 100644
index 0000000..4711cf5
--- /dev/null
+++ b/sepolicy/healthd.te
@@ -0,0 +1 @@
+allow healthd self:capability { dac_override dac_read_search };