Update (git|review).openstack.org links to opendev

This updates links going to git.openstack.org and review.openstack.org
to go to their respective opendev locations to avoid redirects.

Change-Id: I78e3bb5303718962f591117f9c0ee11f2314b128
Closes-Bug: #1833256
diff --git a/doc/source/guides/nova.rst b/doc/source/guides/nova.rst
index 65491d1..2271e23 100644
--- a/doc/source/guides/nova.rst
+++ b/doc/source/guides/nova.rst
@@ -83,7 +83,7 @@
 compute API but is good enough for most API testing, and is also used within
 the nova functional tests themselves so is fairly robust.
 
-.. _fake virt driver: http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/fake.py
+.. _fake virt driver: https://opendev.org/openstack/nova/src/branch/master/nova/virt/fake.py
 
 Configuration
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