Do not calculate useless group metrics

https://bugzilla.redhat.com/show_bug.cgi?id=1455690
https://bugzilla.redhat.com/show_bug.cgi?id=1454456

 - cpu is useless as it counts usagemhz and vm_numvcpus together
 - cpu_cores is useless as it only reports cpu_cores
 - memory is useless as counts used and available together
 - net_io is useless as it only reports net_ui_rate_avg
 - disk_io is useless as it only reports disk_usage_rate_avg
 - storage is useless as it counts used and allocated together
 - fixed is useless as it counts all the fixed metrics together
   (that equals to 4 for each day, not useful)

app/models/chargeable_field.rb

@@ -36,8 +36,7 @@ def adjustment_to(target_unit)
   end
 
   def metric_keys
-    ["#{rate_name}_metric", # metric value (e.g. Storage [Used|Allocated|Fixed])
-     "#{group}_metric"]     # total of metric's group (e.g. Storage Total)
+    ["#{rate_name}_metric"] # metric value (e.g. Storage [Used|Allocated|Fixed])
   end
 
   def cost_keys

spec/models/chargeback_vm_spec.rb

@@ -158,7 +158,6 @@
         expect(subject.memory_allocated_metric).to eq(memory_available)
         used_metric = used_average_for(:derived_memory_used, hours_in_day, @vm1)
         expect(subject.memory_used_metric).to eq(used_metric)
-        expect(subject.memory_metric).to eq(subject.memory_allocated_metric + subject.memory_used_metric)
 
         expect(subject.memory_allocated_cost).to eq(memory_available * hourly_rate * hours_in_day)
         expect(subject.memory_used_cost).to eq(used_metric * hourly_rate * hours_in_day)
@@ -186,7 +185,6 @@
         storage_allocated_cost = vm_allocated_disk_storage * count_hourly_rate * hours_in_day
         expect(subject.storage_allocated_cost).to eq(storage_allocated_cost)
 
-        expect(subject.storage_metric).to eq(subject.storage_allocated_metric + subject.storage_used_metric)
         expect(subject.storage_cost).to eq(subject.storage_allocated_cost + subject.storage_used_cost)
       end
 
@@ -204,7 +202,6 @@
           expect(subject.storage_allocated_metric).to eq(vm_allocated_disk_storage.gigabytes)
           used_metric = used_average_for(:derived_vm_used_disk_storage, hours_in_day, @vm1)
           expect(subject.storage_used_metric).to eq(used_metric)
-          expect(subject.storage_metric).to eq(subject.storage_allocated_metric + subject.storage_used_metric)
 
           expected_value = hourly_fixed_rate * hours_in_day
           expect(subject.storage_allocated_cost).to be_within(0.01).of(expected_value)
@@ -280,7 +277,6 @@
         expect(subject.memory_allocated_metric).to eq(memory_available)
         used_metric = used_average_for(:derived_memory_used, hours_in_month, @vm1)
         expect(subject.memory_used_metric).to be_within(0.01).of(used_metric)
-        expect(subject.memory_metric).to eq(subject.memory_allocated_metric + subject.memory_used_metric)
 
         memory_allocated_cost = memory_available * hourly_rate * hours_in_month
         expect(subject.memory_allocated_cost).to be_within(0.01).of(memory_allocated_cost)
@@ -315,7 +311,6 @@
           expect(subject.storage_allocated_metric).to eq(vm_allocated_disk_storage.gigabytes)
           used_metric = used_average_for(:derived_vm_used_disk_storage, hours_in_month, @vm1)
           expect(subject.storage_used_metric).to be_within(0.01).of(used_metric)
-          expect(subject.storage_metric).to eq(subject.storage_allocated_metric + subject.storage_used_metric)
 
           expected_value = hourly_fixed_rate * hours_in_month
           expect(subject.storage_allocated_cost).to be_within(0.01).of(expected_value)
@@ -330,7 +325,6 @@
         expect(subject.storage_allocated_metric).to eq(vm_allocated_disk_storage.gigabytes)
         used_metric = used_average_for(:derived_vm_used_disk_storage, hours_in_month, @vm1)
         expect(subject.storage_used_metric).to be_within(0.01).of(used_metric)
-        expect(subject.storage_metric).to eq(subject.storage_allocated_metric + subject.storage_used_metric)
 
         expected_value = vm_allocated_disk_storage * count_hourly_rate * hours_in_month
         expect(subject.storage_allocated_cost).to be_within(0.01).of(expected_value)