MFC r326278 (manu):

MFC r326278 (manu):

 growfs: Commit the changes after expanding the partition

 This fix the problem in arm snapshot present since at least 6 months
 where growfs was failing at firstboot and dropped you in a single
 user shell.

Note: In addition to this merge, kern.geom.part.mbr.enforce_chs has
been enabled on the build machine to mitigate against the issue in
the PR referenced.

PR:		226536
Sponsored by:	The FreeBSD Foundation

git-svn-id: svn://svn.freebsd.org/base/stable/10@332731 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f