[contents.php] Fix logical error in getSimpleHTMLDOMCached function (#1974)
[contents.php] Fix logical error in getSimpleHTMLDOMCached function (#1974)

Previously content was only loaded from cache when debug mode was enabled (the opposite of the expected behavior)
ORelio/rss-bridge,kranack/rss-bridge,RSS-Bridge/rss-bridge,kranack/rss-bridge,sebsauvage/rss-bridge,RSS-Bridge/rss-bridge,ORelio/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,RSS-Bridge/rss-bridge,ORelio/rss-bridge,Riduidel/rss-bridge