d851: update fstab

* add recoveryonly to boot and recovery partitions
* update deprecated prefix on usb/externalsd
* set auto for usb/externalsd filesystem

Change-Id: Ie57cfaebd72b5e31398b3dfa9f83918efb6fc16f
d851: update system.prop for LTE

This automatically sets the proper network mode

Change-Id: I4c114d140a410bc60e7e1b436586ef08cd4bfcca
Merge branch 'cm-12.0' of https://github.com/CyanogenMod/android_device_lge_d851 into lollipop