Enforce Golang a, b = b, a swaps

This eliminates the last two remaining three-step value swaps (t =
a; a = b; b = t instead of a, b = b, a) and enables linting to prevent
new ones being added in future.

Signed-off-by: Stephen Kitt <skitt@redhat.com>

hack/golangci.yaml

@@ -432,7 +432,6 @@ linters:
         - typeSwitchVar
         - underef
         - unslice
-        - valSwap
     revive:
       # Only these rules are enabled.
       rules:

hack/golangci.yaml.in

@@ -253,7 +253,6 @@ linters:
         - typeSwitchVar
         - underef
         - unslice
-        - valSwap
     {{- end}}
     revive:
       # Only these rules are enabled.

staging/src/k8s.io/apimachinery/pkg/util/strategicpatch/patch.go

@@ -1827,9 +1827,7 @@ func (ss SortableSliceOfMaps) Less(i, j int) bool {
 }
 
 func (ss SortableSliceOfMaps) Swap(i, j int) {
-	tmp := ss.s[i]
-	ss.s[i] = ss.s[j]
-	ss.s[j] = tmp
+	ss.s[i], ss.s[j] = ss.s[j], ss.s[i]
 }
 
 func deduplicateAndSortScalars(s []interface{}) []interface{} {
@@ -1875,9 +1873,7 @@ func (ss SortableSliceOfScalars) Less(i, j int) bool {
 }
 
 func (ss SortableSliceOfScalars) Swap(i, j int) {
-	tmp := ss.s[i]
-	ss.s[i] = ss.s[j]
-	ss.s[j] = tmp
+	ss.s[i], ss.s[j] = ss.s[j], ss.s[i]
 }
 
 // Returns the type of the elements of N slice(s). If the type is different,