inventory: Ignore errors connecting to libvirt

If one of the VM hosts is offline, we still want to be able to generate
the inventory from the other host.

plugins/inventory/pyrocufflink.py

@@ -101,10 +101,14 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
 
         assert self.inventory
         for uri in uri_list:
-            if read_only:
-                conn = libvirt.openReadOnly(uri)
-            else:
-                conn = libvirt.open(uri)
+            try:
+                if read_only:
+                    conn = libvirt.openReadOnly(uri)
+                else:
+                    conn = libvirt.open(uri)
+            except libvirt.libvirtError as e:
+                log.error('Unable to open to libvirt URI: %s', e)
+                continue
             for dom in conn.listAllDomains():
                 host = Host(dom)
                 state = host.get_state()[0]