Use grpc v1.15.x
What does this MR do?
Fixes errors "Call dropped by load balancing policy error" on GRPC. See https://github.com/grpc/grpc/issues/12506
What are the relevant issue numbers?
Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/52506
Does this MR meet the acceptance criteria?
-
Changelog entry added, if necessary -
Documentation created/updated -
Tests added for this feature/bug -
Conforms to the code review guidelines -
Conforms to the merge request performance guidelines -
Conforms to the style guides -
Conforms to the database guides