SELinux: Add system group to thermald to avoid dac_override denial.

Change helps resolve the following denial.

avc:  denied  { dac_override } for  pid=441 comm="thermald" capability=1  scontext=u:r:thermald:s0 tcontext=u:r:thermald:s0 tclass=capability

A similar change already exists for the hammerhead policy. Future
changes might need to be added here to accommodate additional
dac_override denials that might happen beyond this change. Consult
hammerhead change Ied2293d9effb1b2d9e043e01c08b5e7be407c868 for
some additional insight.

Change-Id: Ica6d657e5c37851b725f0b2bbe6b46d18ceb84bb
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>
diff --git a/init.flo.rc b/init.flo.rc
index 3c7143d..6cc2283 100644
--- a/init.flo.rc
+++ b/init.flo.rc
@@ -428,7 +428,7 @@
 
 service thermald /system/bin/thermald
     class main
-    group radio
+    group radio system
 
 service mpdecision /system/bin/mpdecision --no_sleep --avg_comp
     class main