Fixed help appearance on empty/unknown commands

Change-Id: I709e05b3c2658da7a8b257e2970f5f4da2e05cf2
Related-PROD: PROD-35610
diff --git a/cfg_checker/cfg_check.py b/cfg_checker/cfg_check.py
index 2ce37eb..11190b4 100644
--- a/cfg_checker/cfg_check.py
+++ b/cfg_checker/cfg_check.py
@@ -2,7 +2,8 @@
 import sys
 from logging import DEBUG, INFO
 
-from cfg_checker.cli.command import execute_command, helps, parsers
+from cfg_checker.cli.command import execute_command, helps, parsers, \
+    parsers_inits
 from cfg_checker.common import config, logger, logger_cli
 from cfg_checker.helpers.args_utils import MyParser
 
@@ -54,7 +55,7 @@
             _command,
             help=helps[_command]
         )
-        parsers[_command](_parser)
+        parsers[_command] = parsers_inits[_command](_parser)
 
     # parse arguments
     try:
@@ -71,6 +72,10 @@
         )
         sys.exit(1)
 
+    if not args.command:
+        parser.print_help()
+        logger_cli.info("\n# Please, type a command listed above")
+        sys.exit(1)
     # Pass externally configured values
     config.ssh_uses_sudo = args.sudo