[generic_config_updater] Minor update - No logical code change (sonic-net#2028)

What I did
Missed update from review comments in PR sonic-net#2020
s/os.system("sleep 10s")/time.sleep(10)/

Author: renukamanavalan

generic_config_updater/services_validator.py

@@ -1,4 +1,5 @@
 import os
+import time
 from .gu_common import genericUpdaterLogging
 
 logger = genericUpdaterLogging.get_logger(title="Service Validator")
@@ -33,7 +34,7 @@ def _service_restart(svc_name):
             logger.log(logger.LOG_PRIORITY_ERROR,
                     f"Restart failed for {svc_name} rc={rc} after reset; Pause for 10s & retry",
                     print_to_console)
-            os.system("sleep 10s")
+            time.sleep(10)
             rc = os.system(f"systemctl restart {svc_name}")
 
     if rc == 0:

tests/generic_config_updater/service_validator_test.py

@@ -67,7 +67,6 @@ def mock_os_system_call(cmd):
         { "cmd": "systemctl restart rsyslog", "rc": 1 },         # rsyslog restart; fails
         { "cmd": "systemctl reset-failed rsyslog", "rc": 1 },    # reset; failure here just logs
         { "cmd": "systemctl restart rsyslog", "rc": 1 },         # restart again; fails
-        { "cmd": "sleep 10s", "rc": 0 },                         # sleep; rc ignored
         { "cmd": "systemctl restart rsyslog", "rc": 1 },         # restart again; fails
     ]