vbox_storage: fix coverity issue with overwriting value

Coverity is complaining about overwriting value in 'rc' variable
without using the old value because it somehow doesn't recognize that
the value is used by MACRO. The 'rc' variable is there only for checking
return code so it's save to remove it and make coverity happy.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

src/vbox/vbox_storage.c

@@ -551,7 +551,6 @@ static int vboxStorageVolDelete(virStorageVolPtr vol, unsigned int flags)
     PRUint32  machineIdsSize = 0;
     vboxArray machineIds = VBOX_ARRAY_INITIALIZER;
     vboxIIDUnion hddIID;
-    nsresult rc;
     int ret = -1;
 
     if (!data->vboxObj) {
@@ -568,8 +567,9 @@ static int vboxStorageVolDelete(virStorageVolPtr vol, unsigned int flags)
     }
 
     vboxIIDFromUUID(&hddIID, uuid);
-    rc = gVBoxAPI.UIVirtualBox.GetHardDiskByIID(data->vboxObj, &hddIID, &hardDisk);
-    if (NS_FAILED(rc))
+    if (NS_FAILED(gVBoxAPI.UIVirtualBox.GetHardDiskByIID(data->vboxObj,
+                                                         &hddIID,
+                                                         &hardDisk)))
         goto cleanup;
 
     gVBoxAPI.UIMedium.GetState(hardDisk, &hddstate);
@@ -603,23 +603,22 @@ static int vboxStorageVolDelete(virStorageVolPtr vol, unsigned int flags)
         vboxIIDFromArrayItem(&machineId, &machineIds, i);
 
         if (gVBoxAPI.getMachineForSession) {
-            rc = gVBoxAPI.UIVirtualBox.GetMachine(data->vboxObj, &machineId, &machine);
-            if (NS_FAILED(rc)) {
+            if (NS_FAILED(gVBoxAPI.UIVirtualBox.GetMachine(data->vboxObj,
+                                                           &machineId,
+                                                           &machine))) {
                 virReportError(VIR_ERR_NO_DOMAIN, "%s",
                                _("no domain with matching uuid"));
                 break;
             }
         }
 
-        rc = gVBoxAPI.UISession.Open(data, &machineId, machine);
-
-        if (NS_FAILED(rc)) {
+        if (NS_FAILED(gVBoxAPI.UISession.Open(data, &machineId, machine))) {
             vboxIIDUnalloc(&machineId);
             continue;
         }
 
-        rc = gVBoxAPI.UISession.GetMachine(data->vboxSession, &machine);
-        if (NS_FAILED(rc))
+        if (NS_FAILED(gVBoxAPI.UISession.GetMachine(data->vboxSession,
+                                                    &machine)))
             goto cleanupLoop;
 
         gVBoxAPI.UArray.vboxArrayGet(&hddAttachments, machine,
@@ -633,13 +632,12 @@ static int vboxStorageVolDelete(virStorageVolPtr vol, unsigned int flags)
             if (!hddAttachment)
                 continue;
 
-            rc = gVBoxAPI.UIMediumAttachment.GetMedium(hddAttachment, &hdd);
-            if (NS_FAILED(rc) || !hdd)
+            if (NS_FAILED(gVBoxAPI.UIMediumAttachment.GetMedium(hddAttachment,
+                                                                &hdd)) || !hdd)
                 continue;
 
             VBOX_IID_INITIALIZE(&iid);
-            rc = gVBoxAPI.UIMedium.GetId(hdd, &iid);
-            if (NS_FAILED(rc)) {
+            if (NS_FAILED(gVBoxAPI.UIMedium.GetId(hdd, &iid))) {
                 VBOX_MEDIUM_RELEASE(hdd);
                 continue;
             }
@@ -658,9 +656,8 @@ static int vboxStorageVolDelete(virStorageVolPtr vol, unsigned int flags)
                 gVBoxAPI.UIMediumAttachment.GetPort(hddAttachment, &port);
                 gVBoxAPI.UIMediumAttachment.GetDevice(hddAttachment, &device);
 
-                rc = gVBoxAPI.UIMachine.DetachDevice(machine, controller, port, device);
-                if (NS_SUCCEEDED(rc)) {
-                    rc = gVBoxAPI.UIMachine.SaveSettings(machine);
+                if (NS_SUCCEEDED(gVBoxAPI.UIMachine.DetachDevice(machine, controller, port, device))) {
+                    ignore_value(gVBoxAPI.UIMachine.SaveSettings(machine));
                     VIR_DEBUG("saving machine settings");
                     deregister++;
                     VIR_DEBUG("deregistering hdd:%d", deregister);
@@ -683,9 +680,8 @@ static int vboxStorageVolDelete(virStorageVolPtr vol, unsigned int flags)
 
     if (machineIdsSize == 0 || machineIdsSize == deregister) {
         IProgress *progress = NULL;
-        rc = gVBoxAPI.UIHardDisk.DeleteStorage(hardDisk, &progress);
-
-        if (NS_SUCCEEDED(rc) && progress) {
+        if (NS_SUCCEEDED(gVBoxAPI.UIHardDisk.DeleteStorage(hardDisk, &progress)) &&
+            progress) {
             gVBoxAPI.UIProgress.WaitForCompletion(progress, -1);
             VBOX_RELEASE(progress);
             DEBUGIID("HardDisk deleted, UUID", &hddIID);