sensu_to_whiskerboard.py: use the slug field instead the name field to get the service to check

Signed-off-by: Gaetan Trellu <gaetan.trellu@enovance.com>

sensu_to_whiskerboard.py: ensure that sensu check name is in lower case

Signed-off-by: Gaetan Trellu <gaetan.trellu@enovance.com>

sensu_to_whiskerboard.py: fix the sensu check name lower case part

Signed-off-by: Gaetan Trellu <gaetan.trellu@enovance.com>

sensu_to_whiskerboard.py: Use the slug field instead the name field to get the service to check

Signed-off-by: Gaetan Trellu <gaetan.trellu@enovance.com>