Merge remote-tracking branch 'upstream/master' into patch_dashboard_schema

include/grpc++/server.h

src/core/ext/filters/client_channel/lb_policy.c

src/ruby/ext/grpc/rb_call.c

src/ruby/ext/grpc/rb_call.h

src/ruby/ext/grpc/rb_call_credentials.c

src/ruby/spec/client_server_spec.rb

src/ruby/spec/generic/client_stub_spec.rb