test_l3_longevity.py Indexing with multiple keys need to make single [] to double [[]]

https://stackoverflow.com/questions/60999753/pandas-future-warning-indexing-with-multiple-keys
pandas-dev/pandas#23566

Signed-off-by: Chuck SmileyRekiere <[email protected]>

Author: smileyrekiere

py-scripts/test_l3_longevity.py

@@ -2068,8 +2068,8 @@ def start(self, print_pass=False):
                     all_dl_ports_stations_df.to_csv(all_dl_port_stations_file_name)
 
                     # we should be able to add the values for each eid
-                    all_dl_ports_stations_sum_df = all_dl_ports_stations_df.groupby(['Time epoch'])['Rx-Bps', 'Tx-Bps', 'Rx-Latency', 'Rx-Jitter',
-                                                                                                    'Ul-Rx-Goodput-bps', 'Ul-Rx-Rate-ll', 'Ul-Rx-Pkts-ll', 'Dl-Rx-Goodput-bps', 'Dl-Rx-Rate-ll', 'Dl-Rx-Pkts-ll'].sum()
+                    all_dl_ports_stations_sum_df = all_dl_ports_stations_df.groupby(['Time epoch'])[['Rx-Bps', 'Tx-Bps', 'Rx-Latency', 'Rx-Jitter',
+                                                                                                    'Ul-Rx-Goodput-bps', 'Ul-Rx-Rate-ll', 'Ul-Rx-Pkts-ll', 'Dl-Rx-Goodput-bps', 'Dl-Rx-Rate-ll', 'Dl-Rx-Pkts-ll']].sum()
                     all_dl_ports_stations_sum_file_name = self.outfile[:-4]
                     all_dl_port_stations_sum_file_name = all_dl_ports_stations_sum_file_name + "-dl-all-eids-sum-per-interval.csv"