cfg-checker ceph bench debug part 3

 - cleanup procedure
 - agent json loading updates
 - bool argument detection updates

 Related-PROD: PROD-36669

Change-Id: I9e2417a2bfc03883d9a6ef69f60f000cb5bacf54
diff --git a/cfg_checker/helpers/args_utils.py b/cfg_checker/helpers/args_utils.py
index 84bd6f1..0804617 100644
--- a/cfg_checker/helpers/args_utils.py
+++ b/cfg_checker/helpers/args_utils.py
@@ -27,9 +27,8 @@
 
 
 def get_arg(args, str_arg, nofail=False):
-    _attr = getattr(args, str_arg)
-    if _attr:
-        return _attr
+    if hasattr(args, str_arg):
+        return getattr(args, str_arg)
     else:
         if nofail:
             return None