Increase retry on the v2 leadership query (#5830)
Increase retry on the v2 leadership query (#5830)

Summary:
I have seen a SI test run failed because marathon returned HTTP 502 10 times on v2/leader. Let's try to increase the number of times we retry to see if it helps.

Example of failed run https://jenkins.mesosphere.com/service/jenkins/view/Marathon/job/system-integration-tests/job/marathon-si-dcos-open/job/master/365/consoleFull

JIRA issues:
meln1k/marathon,meln1k/marathon,mesosphere/marathon,janisz/marathon,janisz/marathon,janisz/marathon,meln1k/marathon,janisz/marathon,gsantovena/marathon,gsantovena/marathon,meln1k/marathon,guenter/marathon,mesosphere/marathon,guenter/marathon,guenter/marathon,gsantovena/marathon,gsantovena/marathon,gsantovena/marathon,guenter/marathon,janisz/marathon,meln1k/marathon,mesosphere/marathon,mesosphere/marathon,guenter/marathon,mesosphere/marathon