LU-11773 utils: add PFL flags support to YAML API

LU-11773 utils: add PFL flags support to YAML API

The setstripe YAML interface currently ignores the
lcme_flags field. This means it doesn't work correctly with
some FLR layouts.

Fixing this is a trivial matter of making the YAML layout
generator read & use the lcme_flags field.

Signed-off-by: Patrick Farrell <paf@cray.com>
Change-Id: If15999aa58ac3e31da677bd5d1ef8b063b46b1e5
Reviewed-on: https://review.whamcloud.com/33852
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>