msm8976-common: Grant rmt_storage proper unix perms

Do not grant DAC override permission which would allow this daemon
unix permissions to everything.

avc: denied { dac_override } for pid=2664 comm="rmt_storage" capability=1 scontext=u:r:rmt_storage:s0 tcontext=u:r:rmt_storage:s0 tclass=capability permissive=0

Add wakelock group to access:
/sys/power/wake_lock
-rw-rw----  1 radio  wakelock 4096 2017-06-28 00:37 wake_unlock

Change-Id: Ib02b4aedab479f5ad8aca3a2100b5c489397002a

rootdir/etc/init.qcom.rc

@@ -1371,6 +1371,7 @@ service irsc_util /system/bin/irsc_util "/etc/sec_config"
 service rmt_storage /system/bin/rmt_storage
     class core
     user root
+    group wakelock
     writepid /dev/cpuset/system-background/tasks
 
 service tftp_server /system/bin/tftp_server

sepolicy/rmt_storage.te

@@ -1,3 +1,3 @@
-allow rmt_storage self:capability { dac_override net_raw };
+allow rmt_storage self:capability net_raw;
 
 set_prop(rmt_storage, rmt_storage_prop)