Handle file errors when device path gets unbound

occ-control was asserting when the hwmon path would get removed due to
device being unbound. This change will gracefully handle the path
getting removed / added back.

Tested on Raininer by unbind/bind of devices:
  echo occ-hwmon.2 > /sys/bus/platform/drivers/occ-hwmon/unbind
  echo occ-hwmon.2 > /sys/bus/platform/drivers/occ-hwmon/bind

Change-Id: I46fd2c2c54868ffb8183d3dc49cd0c2751165d3b
Signed-off-by: Chris Cain <cjcain@us.ibm.com>
6 files changed