erasure-code: update links to jerasure upstream

It moved from bitbucket to jerasure.org

Signed-off-by: Loic Dachary <ldachary@redhat.com>
(cherry picked from commit 8e86f901939f16cc9c8ad7a4108ac4bcf3916d2c)
Merge pull request #3264 from dachary/wip-jerasure-firefly

erasure-code: update links to jerasure upstream