[ONNX] Refactor exceptions (#1467)

src/ngraph/frontend/onnx_import/exceptions.hpp

@@ -24,9 +24,9 @@ namespace ngraph
     {
         namespace error
         {
-            struct not_supported_error : ngraph_error
+            struct NotSupported : ngraph_error
             {
-                explicit not_supported_error(const std::string& op_name,
+                explicit NotSupported(const std::string& op_name,
                                       const std::string& name,
                                       const std::string& message)
                     : ngraph_error{op_name + " node (" + name + "): " + message}
@@ -34,19 +34,18 @@ namespace ngraph
                 }
             };
 
-            namespace op
+            namespace parameter
             {
-                struct op_value_error : ngraph_error
+                struct Value : ngraph_error
                 {
-                    explicit op_value_error(const std::string& op_name,
+                    Value(const std::string& op_name,
                           const std::string& name,
                           const std::string& message)
                         : ngraph_error{op_name + " node (" + name + "): " + message}
                     {
                     }
                 };
-
-            } // namespace  op
+            } // namespace paramter
 
         } // namespace  error
 

src/ngraph/frontend/onnx_import/op/batch_norm.hpp

@@ -48,13 +48,13 @@ namespace ngraph
 
                 if (!is_test)
                 {
-                    throw error::not_supported_error("BatchNormalization",
+                    throw error::NotSupported("BatchNormalization",
                                               node.get_name(),
                                               "only 'is_test' mode is currently supported.");
                 }
                 if (!spatial)
                 {
-                    throw error::not_supported_error("BatchNormalization",
+                    throw error::NotSupported("BatchNormalization",
                                               node.get_name(),
                                               "only 'spatial' mode is currently supported.");
                 }