xfs_admin: don't hide the xfs_repair output when upgrading

xfs_admin: don't hide the xfs_repair output when upgrading

Currently, xfs_admin suppresses the output from xfs_repair when it tries
to upgrade a filesystem, and prints a rather unhelpful message if the
upgrade fails.

Neither of these behaviors are useful -- repair can fail for reasons
outside of the filesystem being mounted, and if it does, the admin will
never know what actually happened.

Worse yet, if repair finds corruptions on disk, the upgrade script
silently throws all that away, which means that nobody will ever be able
to report what happened if an upgrade trashes a filesystem.

Therefore, allow the console to capture all of repair's stdout/stderr
reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>