MB-48432: Disk usage analyzer alerts should be windows only

Ensure that calls to is_stale won't crash on windows, by making
accesses to the ns_disksup ets table gated behind macos and linux
only.

Change-Id: Iafcbe858a0158dc57d5006519de2a60c12a636bc
Reviewed-on: http://review.couchbase.org/c/ns_server/+/161532
Well-Formed: Restriction Checker
Well-Formed: Build Bot <[email protected]>
Tested-by: Build Bot <[email protected]>
Tested-by: Bryan McCoid <[email protected]>
Reviewed-by: Aliaksey Artamonau <[email protected]>

Author: bryandmc

src/ns_disksup.erl

@@ -49,11 +49,16 @@ get_disk_data() ->
     end.
 
 is_stale() ->
-    case get_latest_entry() of
-        {none, _} ->
-            true;
-        {Ts, _, Timeout} ->
-            check_staleness(Ts, Timeout * 2)
+    case misc:is_linux() orelse misc:is_macos() of
+        true ->
+            case get_latest_entry() of
+                {none, _} ->
+                    true;
+                {Ts, _, Timeout} ->
+                    check_staleness(Ts, Timeout * 2)
+            end;
+        false ->
+            false
     end.
 
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