staticfiles: remove mapFSRootOpenErr because Go stdlib has fixed the relevant issue (#1919)
staticfiles: remove mapFSRootOpenErr because Go stdlib has fixed the relevant issue (#1919)


yukimochi/caddy,captncraig/caddy,yukimochi/caddy,joshix/caddy,joshix/caddy,captncraig/caddy,yukimochi/caddy,captncraig/caddy,joshix/caddy