Fix bug: do not initialize samples in every iter

scripts-available/CDB_FederatedServerDiagnostics.sql

@@ -146,13 +146,14 @@ AS $$
     rv = plpy.execute(plan, [server_internal], 1)
     port = rv[0]['port']
 
+    n_errors = 0
+    samples = []
+
     for i in range(n_samples):
         s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         s.settimeout(timeout_seconds)
 
         t_start = timer()
-        samples = []
-        n_errors = 0
 
         try:
             s.connect((host, int(port)))