Move kDefaultNumConnections (net/)

When building using jumbo unnamed namespaces gets merged
and variables with the same name conflict. This happens
for the variable kDefaultNumConnections in:
net/third_party/quic/core/congestion_control/cubic_bytes.cc
net/third_party/quic/core/congestion_control/tcp_cubic_sender_bytes.cc

This commit solves the issue by moving the variable
definition to net/third_party/quic/core/quic_constants.h.

Bug: 772146
Change-Id: Ib7c961511823a8ecbc996775485a5fe23649e65e
Reviewed-on: https://chromium-review.googlesource.com/1120169
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Commit-Queue: Oscar Johansson <oscarj@opera.com>
Cr-Commit-Position: refs/heads/master@{#572123}
3 files changed