example userdata line (as needed by MotoX):
/data f2fs /dev/block/platform/msm_sdcc.1/by-name/userdata flags=fsflags="inline_xattr"
Code for parsing flags/options originally based on AOSP fs_mgr sources.
Change-Id: I5fb2b5d5cdd08137e6bf71f0085a3f8aebd889a8