libxl: fix deadlock in libxlReconnectDomain

Use virDomainObjListRemoveLocked instead of virDomainObjListRemove, as
driver->domains is already taken by virDomainObjListForEach.

Above deadlock can be triggered when libvirtd is started after some
domain have been started by hand (in which case driver will not find
libvirt-xml domain config).
Signed-off-by: NMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

src/libxl/libxl_driver.c

@@ -1117,7 +1117,7 @@ libxlReconnectDomain(virDomainObjPtr vm,
 out:
     libxlVmCleanup(driver, vm, VIR_DOMAIN_SHUTOFF_UNKNOWN);
     if (!vm->persistent)
-        virDomainObjListRemove(driver->domains, vm);
+        virDomainObjListRemoveLocked(driver->domains, vm);
     else
         virObjectUnlock(vm);