Fix /sd-ext formatting and backup & restore of user data in recovery

For more indormation:
https://github.com/androidarmv6/android_device_lge_msm7x27-common/commit/29d2130713afb32289234f94d4487bde07e1d68a

Change-Id: I1c0784727dd5739dc7ba0c2bb4a9848b81905cf3