message: Update nGraph tag to v0.2.0
diff: @@ -44,7 +44,7 @@ string(REGEX REPLACE "\n$" "" TENSORFLOW_DIR "${TEMP}")
  ExternalProject_Add(
  ext_ngraph
  GIT_REPOSITORY https://github.com/NervanaSystems/ngraph
  - GIT_TAG v0.2.0-rc0
  + GIT_TAG v0.2.0
  CMAKE_ARGS -DNGRAPH_INSTALL_PREFIX=${CMAKE_CURRENT_BINARY_DIR}/ngraph/ngraph_dist -DNGRAPH_USE_PREBUILT_LLVM=TRUE
  TMP_DIR "${CMAKE_CURRENT_BINARY_DIR}/ngraph/tmp"
  STAMP_DIR "${CMAKE_CURRENT_BINARY_DIR}/ngraph/stamp"
  