tools/scyllatop: log input from collectd for easier debugging

When running with DEBUG verbosity, scyllatop will now log every single
value it receives from collectd. When you suspect that scyllatop is
somehow distorting values, this is a good way to check it.

Signed-off-by: Yoav Kleinberger <yoav@scylladb.com>
Message-Id: <1463320730-6631-1-git-send-email-yoav@scylladb.com>

tools/scyllatop/metric.py

@@ -30,6 +30,7 @@ class Metric(object):
             key = match.groupdict()['key']
             value = match.groupdict()['value']
             self._status[key] = value
+            logging.debug( '{}: {}'.format( self.symbol, line.strip() ) )
 
     @classmethod
     def discover(cls, collectd):