erasure-code: jerasure and gf-complete moved to ceph namespace

for maintenance purposes

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #1491 from dachary/wip-submodules

erasure-code: jerasure and gf-complete moved to ceph namespace

Reviewed-by:  Alfredo Deza <alfredo.deza@inktank.com>