Add nGraph Python API versioning (#7539)

* Expose ngraph_version_string as ngraph.__version__

* Fix linking error on CentOS

runtime/bindings/python/src/compatibility/ngraph/__init__.py

@@ -4,11 +4,10 @@
 """ngraph module namespace, exposing factory functions for all ops and other classes."""
 # noqa: F401
 
-from pkg_resources import get_distribution, DistributionNotFound
-
 try:
-    __version__ = get_distribution("ngraph-core").version
+    from ngraph.impl import util
-except DistributionNotFound:
+    __version__ = util.get_ngraph_version_string()
+except ImportError:
     __version__ = "0.0.0.dev0"
 
 

runtime/bindings/python/src/compatibility/pyngraph/util.cpp

@@ -7,6 +7,7 @@
 #include <pybind11/numpy.h>
 
 #include "ngraph/validation_util.hpp"
+#include "openvino/core/version.hpp"
 
 namespace py = pybind11;
 
@@ -23,12 +24,10 @@ void regmodule_pyngraph_util(py::module m) {
             py::arg("output"),
             R"(
                     Runs an estimation of source tensor.
-
                     Parameters
                     ----------
                     output : Output
                         output node
-
                     Returns
                     ----------
                     get_constant_from_source : Constant or None
@@ -36,4 +35,8 @@ void regmodule_pyngraph_util(py::module m) {
                         they are the same returns Constant operation
                         from the resulting bound, otherwise Null.
                 )");
+
+    mod.def("get_ngraph_version_string", []() -> std::string {
+        return ov::get_openvino_version()->buildNumber;
+    });
 }

runtime/bindings/python/src/compatibility/pyngraph/util.py

@@ -1,8 +0,0 @@
-# Copyright (C) 2018-2021 Intel Corporation
-# SPDX-License-Identifier: Apache-2.0
-
-# flake8: noqa
-
-from _pyngraph import util
-
-numpy_to_c = util.numpy_to_c