persist.mmc.* only set in init

Bug: 26976972
Change-Id: I0e44bfc6774807a3bd2ba05637a432675d855118
diff --git a/property_contexts b/property_contexts
index 47c3cf7..9e936ca 100644
--- a/property_contexts
+++ b/property_contexts
@@ -41,6 +41,7 @@
 persist.logd.           u:object_r:logd_prop:s0
 persist.logd.security   u:object_r:device_logging_prop:s0
 persist.log.tag         u:object_r:logd_prop:s0
+persist.mmc.            u:object_r:mmc_prop:s0
 persist.sys.            u:object_r:system_prop:s0
 persist.service.        u:object_r:system_prop:s0
 persist.service.bdroid. u:object_r:bluetooth_prop:s0