component/haproxy: version up 2.0.15.

also add CPU=native for possibly better performance.
6 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS.SlapRunner.ResilienceTest-Master

00:31:04

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:08:50

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

04:38:30

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

02:16:21

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

05:42:44

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

02:45:13