ext4_utils: Add support for wipe option, and wipe by default in recovery

Adds a -w option to make_ext4fs, which will attempt to use the
BLKSECDISCARD ioctl to erase the partition in order to avoid
leaving old data where it could be recovered, and to improve
wear levelling after a reformat.

Also causes factory reset through recovery to do a wipe.

Change-Id: Ibe34bbd84552e526be6bd041024a950806aca6b4
11 files changed