template: use pointer values for gid and uid (#14203)

When a Nomad agent starts and loads jobs that already existed in the
cluster, the default template uid and gid was being set to 0, since this
is the zero value for int. This caused these jobs to fail in
environments where it was not possible to use 0, such as in Windows
clients.

In order to differentiate between an explicit 0 and a template where
these properties were not set we need to use a pointer.

jobspec2/helper_test.go

@@ -0,0 +1,5 @@
+package jobspec2
+
+func intToPtr(v int) *int {
+	return &v
+}

jobspec2/parse_job.go

@@ -107,12 +107,6 @@ func normalizeTemplates(templates []*api.Template) {
 		if t.Perms == nil {
 			t.Perms = stringToPtr("0644")
 		}
-		if t.Uid == nil {
-			t.Uid = intToPtr(-1)
-		}
-		if t.Gid == nil {
-			t.Gid = intToPtr(-1)
-		}
 		if t.Splay == nil {
 			t.Splay = durationToPtr(5 * time.Second)
 		}
@@ -127,10 +121,6 @@ func boolToPtr(v bool) *bool {
 	return &v
 }
 
-func intToPtr(v int) *int {
-	return &v
-}
-
 func stringToPtr(v string) *string {
 	return &v
 }