scanner: inform about the progress of the measurements

When a new loop starts and when it ends, with the number of relays
measured and the time it took.

sbws/core/scanner.py

@@ -345,6 +345,7 @@ def run_speedtest(args, conf):
     while True:
         num_relays = 0
         loop_tstart = time.time()
+        log.info("Starting a new loop to measure relays.")
         for target in rp.best_priority():
             num_relays += 1
             log.debug('Measuring %s %s', target.nickname,
@@ -364,7 +365,7 @@ def run_speedtest(args, conf):
             pending_results = [r for r in pending_results if not r.ready()]
         loop_tstop = time.time()
         loop_tdelta = (loop_tstop - loop_tstart) / 60
-        log.debug("Measured %s relays in %s minutes", num_relays, loop_tdelta)
+        log.info("Measured %s relays in %s minutes", num_relays, loop_tdelta)
 
 
 def gen_parser(sub):