Increased timeout in `generate-endpoint-help.py`.
Increased timeout in `generate-endpoint-help.py`.

In CI starting master or agent process often took longer than the
allowed 10s which then lead to query timeouts and failed builds.

This patch increases the allowed time from 10s to 10min which should
allow the script to run to completion on even the most adverse machines.

Review: https://reviews.apache.org/r/70105/

reneploetz/mesos,gsantovena/mesos,dforsyth/mesos,kaysoky/mesos,reneploetz/mesos,kaysoky/mesos,dforsyth/mesos,reneploetz/mesos,Gilbert88/mesos,jpeach/mesos,gsantovena/mesos,jpeach/mesos,abudnik/mesos,gsantovena/mesos,dforsyth/mesos,reneploetz/mesos,Gilbert88/mesos,jpeach/mesos,kaysoky/mesos,chhsia0/mesos,chhsia0/mesos,jpeach/mesos,jpeach/mesos,chhsia0/mesos,Gilbert88/mesos,kaysoky/mesos,abudnik/mesos,chhsia0/mesos,Gilbert88/mesos,abudnik/mesos,Gilbert88/mesos,kaysoky/mesos,abudnik/mesos,abudnik/mesos,reneploetz/mesos,chhsia0/mesos,abudnik/mesos,dforsyth/mesos,gsantovena/mesos,jpeach/mesos,chhsia0/mesos,gsantovena/mesos,kaysoky/mesos,Gilbert88/mesos,Gilbert88/mesos,jpeach/mesos,reneploetz/mesos,gsantovena/mesos,abudnik/mesos,reneploetz/mesos,chhsia0/mesos,kaysoky/mesos,dforsyth/mesos,dforsyth/mesos,gsantovena/mesos,dforsyth/mesos