Merge branch 'error' into reuse_port

BUILD

Makefile

binding.gyp

build.yaml

config.m4

gRPC.podspec

grpc.def

grpc.gemspec

include/grpc/impl/codegen/log.h

include/grpc/support/avl.h

package.xml

src/core/ext/census/grpc_filter.c

src/core/ext/client_config/channel_connectivity.c

src/core/ext/client_config/client_channel.c

src/core/ext/client_config/lb_policy.c

src/core/ext/client_config/lb_policy.h

src/core/ext/client_config/subchannel.c

src/core/ext/client_config/subchannel.h

src/core/ext/client_config/subchannel_call_holder.c

src/core/ext/lb_policy/pick_first/pick_first.c