treewide: fix %v in cases where we should use %w

We should always use %w when using fmt.Errorf as you can use error.Is to
compare the underlying error. When printing an error the use of %w is
wrong and should be replaced with %v.

Change-Id: I741111bd91dcee4099144d2ecaffa879fdbb34a2
Reviewed-on: https://review.monogon.dev/c/monogon/+/2993
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/node/core/clusternet/clusternet.go b/metropolis/node/core/clusternet/clusternet.go
index 1c3c7b3..96a500d 100644
--- a/metropolis/node/core/clusternet/clusternet.go
+++ b/metropolis/node/core/clusternet/clusternet.go
@@ -230,11 +230,11 @@
 
 		if shouldAdd {
 			if err := netlink.AddrAdd(loInterface, addr); err != nil {
-				return fmt.Errorf("assigning extra loopback IP: %v", err)
+				return fmt.Errorf("assigning extra loopback IP: %w", err)
 			}
 		} else {
 			if err := netlink.AddrDel(loInterface, addr); err != nil {
-				return fmt.Errorf("removing extra loopback IP: %v", err)
+				return fmt.Errorf("removing extra loopback IP: %w", err)
 			}
 		}
 	}