erasure-code: update jerasure / gf-complete submodules

For compilation warning patches.

http://tracker.ceph.com/issues/7909 Fixes #7909

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #1568 from dachary/wip-jerasure-warnings

erasure-code: update jerasure / gf-complete submodules

Reviewed-by: Sage Weil <sage@inktank.com>