Replace sleep code

[PhilipMay]

IMO this code:

prometheus-smartctl/smartprom.py

Lines 176 to 184 in 3fbd7bb

	collect()
	start_time = time.time()
	while True:
	elapsed_time = time.time() - start_time
	if elapsed_time > 20.0:
	start_time = time.time()
	collect()
	time.sleep(0.1)

can be replaced by just this:

    while True:
        collect()
        time.sleep(20)

What do you think?

[ngosang]

Closed by #29