Fix PHP warnings in XMDS
Fix PHP warnings in XMDS

(cherry picked from commit 30ea3433e2556c4ed22edbd9095e9ac513430ea2)

xibosignage/xibo-cms,xibosignage/xibo-cms,dasgarner/xibo-cms,xibosignage/xibo-cms,dasgarner/xibo-cms,alexharrington/xibo-cms,dasgarner/xibo-cms,dasgarner/xibo-cms,dasgarner/xibo-cms,alexharrington/xibo-cms,alexharrington/xibo-cms,xibosignage/xibo-cms,xibosignage/xibo-cms,xibosignage/xibo-cms,alexharrington/xibo-cms,dasgarner/xibo-cms,alexharrington/xibo-cms