ui: qemu pci edit: remove the default PCI domain again before saving

The PCI selector shows the IDs of the devices including the domain, so
the default '0000' domain was removed again before saving, as it is
optional in the hostpci option.

Since the refactoring in commit a7ec3666 ("ui: qemu/PCI Edit: code
cleanup/refactoring/modernize"), the result of the replace call is not
assigned anymore, so the domain is kept and a device that was
configured as '01:00.0' gets saved as '0000:01:00.0' on any edit of
the passthrough device.

Assign the result again, so the domain is only kept if it is not the
default one, like before.

Fixes: a7ec3666 ("ui: qemu/PCI Edit: code cleanup/refactoring/modernize")
Signed-off-by: Michal Fox <me@dualfroz.com>

www/manager6/qemu/PCIEdit.js

@@ -109,7 +109,9 @@ Ext.define('PVE.qemu.PCIInputPanel', {
                 // FIXME: what if no confid was found??
             }
 
-            values.host?.replace(/^0000:/, ''); // remove optional '0000' domain
+            if (values.host) {
+                values.host = values.host.replace(/^0000:/, ''); // remove optional '0000' domain
+            }
 
             if (values.multifunction && values.host) {
                 values.host = values.host.substring(0, values.host.indexOf('.')); // skip the '.X'