hammerhead: Set vendor security patch level
hammerhead: Set vendor security patch level

From ro.build.version.security_patch in build.prop from the latest 6.0.1 factory image

Change-Id: I127e8997716048b3587bf863b99f95f3f487f9e5

maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead