[PLAT-15593][PLAT-15544] fixed some health check issues around clock …

…sync.

Summary:
First there is an issue with how we get clock drift from ntpq. Fixed error in the command ran.

Second, there is an issue with how we detect if a service file exists. We also need to validate
if the command returned "Error".

Test Plan:
validated health checks pass for non-systemd universes
validated ntpq gets clock drift correctly

Reviewers: nsingh, muthu, yash.priyam, ysharmar

Reviewed By: muthu

Subscribers: yugaware

Differential Revision: https://phorge.dev.yugabyte.com/D38679

managed/src/main/resources/health/node_health.py.template

@@ -1880,10 +1880,10 @@ class NodeChecker():
             root_out = self._check_output(root_cmd)
             user_out = self._check_output(user_cmd)
             success = True
-            if "0 unit files listed" not in root_out:
+            if "0 unit files listed" not in root_out and "Error" not in root_out:
                 if not self._check_unit_for_preexec(service, user=False):
                     errors.append("%s has no clock_sync script ExecStartPre" % service)
-            elif "0 unit files listed" not in user_out:
+            elif "0 unit files listed" not in user_out and "Error" not in user_out:
                 if not self._check_unit_for_preexec(service, user=True):
                     errors.append("%s has no clock_sync script ExecStartPre" % service)
             else:
@@ -2134,7 +2134,7 @@ def _ntp_get_clock_drift_ms():
     ntp_out = check_output("systemctl status ntp.service", env)
     ntpd_out = check_output("systemctl status ntpd.service", env)
     if "Active: active" in ntp_out or "Active: active" in ntpd_out:
-        out = check_output("ntpq -p | awk 'NR==3' {print $9}'", env)
+        out = check_output("ntpq -p | awk 'NR==3 {print $9}'", env)
         if "Error" not in out:
           return int(float(out)*1000) # Convert seconds to milliseconds
     return "Failed to get clock drift from ntp(d)"