Have Immediate Shutdown call the chassis object

"Immediate Shutdown" on the GUI should be a hard power off
and differ from the "Orderly shutdown".

From https://github.com/openbmc/docs/blob/master/host-management.md:

To issue a hard power off (accomplished by powering off the chassis):

curl -c cjar -b cjar -k -H "Content-Type: application/json" -X PUT \
  -d '{"data": "xyz.openbmc_project.State.Chassis.Transition.Off"}' \
  https://${bmc}/xyz/openbmc_project/state/chassis0/attr/RequestedPowerTransition

There was already an unused "chassisPowerOff" function, reworked it to
call the chassis object.

Resolves openbmc/openbmc#2890

Tested: Pointed the local GUI to a Witherspoon system and
verfied the correct rest call was made and the system hard
powered off.
Change-Id: Ibdb712656930a62e34603daa17df0d3116c86d92
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/app/common/services/api-utils.js b/app/common/services/api-utils.js
index 63bf71d..730b2d8 100644
--- a/app/common/services/api-utils.js
+++ b/app/common/services/api-utils.js
@@ -237,19 +237,19 @@
               },
               chassisPowerOff: function(callback){
                 $http({
-                  method: 'POST',
-                  url: DataService.getHost() + "/xyz/openbmc_project/state/host0",
+                  method: 'PUT',
+                  url: DataService.getHost() + "/xyz/openbmc_project/state/chassis0/attr/RequestedPowerTransition",
                   headers: {
                       'Accept': 'application/json',
                       'Content-Type': 'application/json'
                   },
                   withCredentials: true,
-                  data: JSON.stringify({"data": []})
+                  data: JSON.stringify({"data": "xyz.openbmc_project.State.Chassis.Transition.Off"})
                 }).then(function(response){
                       var json = JSON.stringify(response.data);
                       var content = JSON.parse(json);
                       if(callback){
-                          return callback(content.data.CurrentPowerState);
+                          return callback(content.status);
                       }
                 }, function(error){
                   if(callback){