Merge pull request #9655 from markdroth/remove_initial_connect_string

BUILD

CMakeLists.txt

Makefile

binding.gyp

build.yaml

config.m4

gRPC-Core.podspec

grpc.gemspec

package.xml

src/core/ext/client_channel/connector.h

src/core/ext/client_channel/default_initial_connect_string.c

src/core/ext/client_channel/initial_connect_string.c

src/core/ext/client_channel/initial_connect_string.h

src/core/ext/client_channel/subchannel.c

src/core/ext/transport/chttp2/client/chttp2_connector.c

src/python/grpcio/grpc_core_dependencies.py

test/core/client_channel/BUILD

test/core/client_channel/set_initial_connect_string_test.c

tools/doxygen/Doxyfile.core.internal

tools/run_tests/generated/sources_and_headers.json