save total_duration as int into the db

without that, the DB saves it as float even though the column type is
INT.

requires a run of

sqlite3 proxylist.sqlite "update proxylist set success_count=0,total_duration=0"

to fix existing entries.

proxywatchd.py

@@ -77,7 +77,7 @@ class WorkerJob():
 				self.proto = proto
 				self.failcount = 0
 				self.success_count = self.success_count + 1
-				self.total_duration += duration*1000
+				self.total_duration += int(duration*1000)
 				_log('%s://%s; c: %s; d: %.2f sec(s); tor: %s; srv: %s; recv: %s' % (proto, self.proxy, match, duration, tor, srv, recv), 'xxxxx')
 		except KeyboardInterrupt as e:
 			raise e