fstab: remove discard flag
fstab: remove discard flag

With fstrim ( http://git.io/CFXF2Q ) we no longer need the discard
flag. This should provide performance improvements with small file
handling.

Change-Id: I45eeeb3cd0aaa445db924b36044e2a507ed9cd7b

mdmower/android_device_htc_fireball,CyanogenMod/android_device_htc_fireball,cyandream-devices/android_device_htc_fireball,Beeko/android_device_htc_fireball,cyandream-devices/android_device_htc_fireball,mdmower/android_device_htc_fireball,CyanogenMod/android_device_htc_fireball,Beeko/android_device_htc_fireball