[VOL-2870]v2

- Enable YAML/JSON linting
- Fix formatting in files
- Fix minor shellcheck issue on voltha tool

Change-Id: I6d29830a7b60c32e09aca49b22125c350c4d1693
diff --git a/Makefile b/Makefile
index 4c61b4e..e22fe44 100644
--- a/Makefile
+++ b/Makefile
@@ -6,9 +6,9 @@
 SHELL = bash -eu -o pipefail
 
 .DEFAULT_GOAL := help
-.PHONY: test shellcheck yamllint jsonlint help
+.PHONY: test shellcheck yamllint lint-json help
 
-test: shellcheck ## run all tests
+test: shellcheck lint-json yamllint ## run all tests
 
 SHELL_FILES := voltha
 shellcheck: ## check shell scripts with shellcheck
@@ -23,11 +23,14 @@
     -s $(YAML_FILES)
 
 JSON_FILES ?= $(shell find . -type f -name '*.json' -print )
-jsonlint: ## lint check JSON files with yamllint
-	echo "Not supported yet, would check these files: $(JSON_FILES)"
+lint-json: ## lint check JSON files by loading them with python
+	for jsonfile in $(JSON_FILES); do \
+		echo "Validating json file: $$jsonfile" ;\
+		python -m json.tool $$jsonfile > /dev/null ;\
+	done
 
-help: ## Print help for each target
+help: ## Print help for each Makefile target
 	@echo kind-voltha Makefile targets
 	@echo
-	@grep '^[[:alpha:]_-]*:.* ##' $(MAKEFILE_LIST) \
+	@grep '^[[:alnum:]_-]*:.* ##' $(MAKEFILE_LIST) \
     | sort | awk 'BEGIN {FS=":.* ## "}; {printf "%-25s %s\n", $$1, $$2};'