fs_mgr: pass sehandle to ext4 format routine

When fs_mgr_do_format() is executed, fs_mgr creates a new
blank data file system. However, that filesystem is not
labeled and causes some unlabeled denials on early boot.

Example Denial:
avc: denied { search } for pid=2535 comm="logd" name="/" dev="mmcblk0p9" ino=2 scontext=u:r:logd:s0 tcontext=u:object_r:unlabeled:s0 tclass=dir permissive=1

To correct this, pass sehandle to the internal ext4 routine.
This way the ext4 filesystem will be labeled at creation and
the root inode will have a label.

Change-Id: Ieeecaa8bbc258e6d743d281dd956bdaca98b365f
Signed-off-by: William Roberts <william.c.roberts@intel.com>