LU-13717 sec: process Lustre enc inodes as normal enc inodes

LU-13717 sec: process Lustre enc inodes as normal enc inodes

Lustre encrypted inodes have the EXT4_ENCRYPT_FL flag set on disk.
This makes it possible for e2fsprogs to consider them as normal
encrypted inodes.
But as Lustre encrypted inodes may contain illegal characters in their
names, it is also needed to escape non-printable characters in
linkEA.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: Iaf495f399e38e3ca7914b92059607d4babc1ad43
Reviewed-on: https://review.whamcloud.com/45212
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>