TCA spams journald with debug messages

Hi,

While manually testing Tails, I noticed systemd's journal gets a lot of entries related to TCA:

Oct 24 13:41:13 amnesia tca[8892]: DEBUG:stem:GETCONF disablenetwork (runtime: 0.0014)
Oct 24 13:41:14 amnesia tca[8892]: DEBUG:stem:GETCONF disablenetwork (runtime: 0.0146)
Oct 24 13:41:15 amnesia tca[8892]: DEBUG:stem:GETCONF disablenetwork (runtime: 0.0184)
Oct 24 13:41:16 amnesia tca[8892]: DEBUG:stem:GETCONF disablenetwork (runtime: 0.0120)
Oct 24 13:41:17 amnesia tca[8892]: DEBUG:stem:GETCONF disablenetwork (runtime: 0.0132)

The startup DEBUG message, before Tor is available, might make sense, however I feel like one entry a second for a normal operation is too much.

I'd suggest disabling DEBUG messages altogether, or limiting it to the startup operation.

Impacts:

• readability of Whisperback logs
• readability of logs in general