message: Move opentracing into its own build traget.
diff: @@ -12,13 +12,10 @@ envoy_cc_library(
  name = "http_tracer_lib",
  srcs = [
  "http_tracer_impl.cc",
  - "opentracing_driver_impl.cc",
  ],
  hdrs = [
  "http_tracer_impl.h",
  - "opentracing_driver_impl.h",
  ],
  - external_deps = ["opentracing"],
  deps = [
  "//include/envoy/local_info:local_info_interface",
  "//include/envoy/runtime:runtime_interface",
  @@ -42,6 +39,20 @@ envoy_cc_library(
  ],
  )
  +envoy_cc_library(
  + name = "opentracing_driver_lib",
  + srcs = [
  + "opentracing_driver_impl.cc",
  + ],
  + hdrs = [
  + "opentracing_driver_impl.h",
  + ],
  + external_deps = ["opentracing"],
  + deps = [
  + ":http_tracer_lib",
  + ],
  +)
  +
  envoy_cc_library(
  name = "lightstep_tracer_lib",
  srcs = [
  @@ -53,5 +64,6 @@ envoy_cc_library(
  external_deps = ["lightstep"],
  deps = [
  ":http_tracer_lib",
  + ":opentracing_driver_lib",
  ],
  )
  