Add missing 'goto error' in QEMU command line building

If reporting case of a binary not supporting KVM or kQEMU, libvirt
forgot to jump to the error branch for cleanup

src/qemu/qemu_command.c

@@ -4449,6 +4449,7 @@ qemuBuildCommandLine(virConnectPtr conn,
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("the QEMU binary %s does not support kqemu"),
                            emulator);
+            goto error;
         }
         break;
 
@@ -4462,6 +4463,7 @@ qemuBuildCommandLine(virConnectPtr conn,
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                            _("the QEMU binary %s does not support kvm"),
                            emulator);
+            goto error;
         }
         break;