Do not emit warning for broken temperatures on Linux

[giampaolo]

A lot of things can go wrong when reading temperatures from /sys/class/hwmon/* filesystem:

psutil/psutil/_pslinux.py

Lines 1175 to 1184 in 45c0ebc

	except (IOError, OSError) as err:
	# A lot of things can go wrong here, so let's just skip the
	# whole entry.
	# https://github.com/giampaolo/psutil/issues/1009
	# https://github.com/giampaolo/psutil/issues/1101
	# https://github.com/giampaolo/psutil/issues/1129
	# https://github.com/giampaolo/psutil/issues/1245
	warnings.warn("ignoring %r for file %r" % (err, path),
	RuntimeWarning)
	continue

See re. #1009, #1101, #1129, #1245, #1203. This seems to be particularly painful for Glances as well: nicolargo/glances#1203. As such I think it makes sense to simply skip the broken entry without emitting any warning.

[giampaolo]

On a second though, it is already kinda of a shame we have to swallow the exception. Suppressing the warning would be even worse.