address comments

Signed-off-by: Mai Bui <maibui@microsoft.com>

config/main.py

@@ -1656,18 +1656,17 @@ def load_mgmt_config(filename):
         clicommon.run_command(command, display_cmd=True, ignore_error=True)
     if len(config_data['MGMT_INTERFACE'].keys()) > 0:
         filepath = '/var/run/dhclient.eth0.pid'
-        if os.path.isfile(filepath):
-            out0, rc0 = clicommon.run_command(['cat', filepath], display_cmd=True, return_cmd=True)
-            if rc0 == 0:
-                out1, rc1 = clicommon.run_command(['kill', out0], return_cmd=True)
-                if rc1 == 0:
-                    clicommon.run_command(['rm', '-f', filepath], display_cmd=True, return_cmd=True)
-                else:
-                    sys.exit('Exit: {}. Command: kill {} failed.'.format(rc1, out0))
-            else:
-                sys.exit('Exit: {}. Command: cat {} failed.'.format(rc0, filepath))
-        else:
+        if not os.path.isfile(filepath):
             sys.exit('File {} does not exist'.format(filepath))
+
+        out0, rc0 = clicommon.run_command(['cat', filepath], display_cmd=True, return_cmd=True)
+        if rc0 != 0:
+            sys.exit('Exit: {}. Command: cat {} failed.'.format(rc0, filepath))
+
+        out1, rc1 = clicommon.run_command(['kill', str(out0).strip('\n')], return_cmd=True)
+        if rc1 != 0:
+            sys.exit('Exit: {}. Command: kill {} failed.'.format(rc1, out0))
+        clicommon.run_command(['rm', '-f', filepath], display_cmd=True, return_cmd=True)
     click.echo("Please note loaded setting will be lost after system reboot. To preserve setting, run `config save`.")
 
 @config.command("load_minigraph")