Corrects exercise_set_umask_0022 unit test

The ctl_gateway_generate_and_read_tls_files unit test was broken by the
exercise_set_umask_0022 unit test because it sleeps for 2 minutes during
which time the exercise_set_umask_0022 unit test ran and changed the
umask state prior to ctl_gateway_generate_and_read_tls_files resuming.
This makes the exercise_set_umask_0022 unit test put the umask back into
the state it was when it started.

Signed-off-by: Jason Heath <[email protected]>

components/core/src/util/posix_perm.rs

@@ -204,10 +204,11 @@ mod tests {
 
         // There's no "reasonable" way I've found to get the current umask so I'm just exploiting
         // what I know about the umask system call to set it so that we have a known umask value.
-        let _ = umask(0o0777).unwrap();
 
+        let unknown_umask = umask(0o0777).unwrap();
         let known_umask = set_umask_0022().unwrap();
         let umask_0022 = umask(0o0777).unwrap();
+        let _ = umask(unknown_umask).unwrap();
 
         assert_eq!(known_umask, 0o0777);
         assert_eq!(umask_0022, 0o0022);