component/h2o: Fix compilation

The development of this component happened in environment which had a lot
of libraries available.
18 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS.SlapRunner.ResilienceTest-Master

00:27:49

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:08:56

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

05:11:55

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

01:23:47

passed SlapOS.SlapRunner.ResilienceTest-Master

00:32:02

passed SlapOS.SlapRunner.ResilienceTest-Master

00:29:23

passed SlapOS.SlapRunner.ResilienceTest-Master

00:27:04

passed SlapOS.SlapRunner.ResilienceTest-Master

00:26:06

passed SlapOS.SlapRunner.ResilienceTest-Master

00:27:05

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:08:23

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:07:55

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:06:42

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:18:39

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:05:51

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

04:02:32

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python2

05:30:55

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

01:45:57

failed SlapOS.SoftwareReleases.IntegrationTest-Master.Python3

01:45:22