message: Fix due to Poplar DeviceSet -> DeviceManager
  Summary: Simple name change
  Test Plan: Just compile
  Reviewers: georgep
diff: @@ -33,7 +33,7 @@ limitations under the License.
  #include <string.h>
  -#include <poplar/DeviceSet.hpp>
  +#include <poplar/DeviceManager.hpp>
  #include <poplar/IPUModel.hpp>
  #include <poplar/Tensor.hpp>
  @@ -266,7 +266,8 @@ Status PoplarExecutor::ConfigurePoplarDevice(
  tensorflow::IPUOptions::DeviceConfig::Type type = cfg.type();
  - static poplar::DeviceSet device_set = poplar::DeviceSet::getDeviceSet();
  + static poplar::DeviceManager device_mgr =
  + poplar::DeviceManager::getDeviceManager();
  int num_ipus = cfg.ipu_model_config().num_ipus();
  int tiles_per_ipu = cfg.ipu_model_config().tiles_per_ipu();
  @@ -275,8 +276,8 @@ Status PoplarExecutor::ConfigurePoplarDevice(
  num_ipus = 1;
  }
  - static auto device_list = device_set.getDevices(poplar::TargetType::IPU,
  - num_ipus);
  + static auto device_list =
  + device_mgr.getDevices(poplar::TargetType::IPU, num_ipus);
  if (type == tensorflow::IPUOptions::DeviceConfig::DEFAULT) {
  if (device_list.size() > 0) {
  @@ -302,7 +303,7 @@ Status PoplarExecutor::ConfigurePoplarDevice(
  // Temporary fix to prevent many long compilation times
  if (tiles_per_ipu == 0) {
  - tiles_per_ipu = 4;
  + tiles_per_ipu = 8;
  }
  if (tiles_per_ipu > 0) {
  