resolved html docs build failure with doxy-code dependency (#499)

fixed sphinx_doc target in the contrib/docker/Makefile to build the docker image as a dependency

removed doxygen_doc target from the contrib/docker/Makefile as it is included with make sphinx_doc as a dependency for make html

contrib/docker/Makefile

@@ -79,19 +79,9 @@ build_docker_image: expand_dockerfile_templates
 build_docker: build_docker_image
 
 # Build docs
-docs: sphinx_doc doxygen_doc
+docs: sphinx_doc
 
-doxygen_doc:
-	# doxygen html docs build
-	docker run --rm --tty \
-            ${VOLUME} \
-	    ${DOCKER_RUN_ENV} \
-            --env RUN_UID="$(shell id -u)" \
-            --env RUN_CMD="set -e ; set -o pipefail ; cd ${DOCKUSER_HOME}/ngraph-cpp-test/doc/doxygen; env VERBOSE=1 make html 2>&1 | tee make_sphinx_html.log" \
-            "build_ngraph_cpp:${DBUILD_VERSION}" \
-	    sh -c "${DOCKUSER_HOME}/ngraph-cpp-test/contrib/docker/run_as_user.sh"
-
-sphinx_doc:
+sphinx_doc: build_docker_image
 	# sphinx html docs build
 	docker run --rm --tty \
             ${VOLUME} \

doc/sphinx/Makefile

@@ -19,12 +19,6 @@ help:
 %: Makefile
 	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
 
-
-doxy-code:
-	$(Q)(cat ngraph.doxyfile ; echo "STRIP_FROM_PATH=${NGRAPH_BASE}" ) | doxygen -  2>&1 | tee doc.log
-
-doxy: doxy-code
-
 clean:
 	@rm -rf $(BUILDDIR)/*
 	@rm -rf html
@@ -32,7 +26,10 @@ clean:
 	@rm -rf doxygen
 	@rm -rf latex
 
-htmldocs: doxy html
+doxy-code:
+	$(Q)(cat ngraph.doxyfile ; echo "STRIP_FROM_PATH=${NGRAPH_BASE}" ) | doxygen -  2>&1 | tee doc.log
+
+html: doxy-code
 
 pickle:
 	$(SPHINXBUILD) -b pickle $(ALLSPHINXOPTS) $(BUILDDIR)/pickle