cgroup: Fix possible bug as a result of code motion for vcpu cgroup setup

Commit id '90b721e4' moved where the virCgroupAddTask was made until
after the check for the vcpupin checks. However, in doing so it missed
an option where if the cpumap didn't exist, then the code would continue
back to the top of the current vcpu loop. The results was that the
virCgroupAddTask wouldn't be called.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

src/qemu/qemu_cgroup.c

@@ -1079,10 +1079,7 @@ qemuSetupCgroupForVcpu(virDomainObjPtr vm)
                 }
             }
 
-            if (!cpumap)
-                continue;
-
-            if (qemuSetupCgroupCpusetCpus(cgroup_vcpu, cpumap) < 0)
+            if (cpumap && qemuSetupCgroupCpusetCpus(cgroup_vcpu, cpumap) < 0)
                 goto cleanup;
         }