chkconfig.ltx: add package filehook

filehook.sty is required when you use non-TeX fonts and also the non-TeX math default font
In the same context LyX requires the font "latinmodern-math.otf", but we can currently not check for it, see my post to the list

lib/chkconfig.ltx

@@ -307,6 +307,7 @@
 \TestPackage[iso-8859-7.def]{greek-inputenc}
 \TestPackage{fancybox}
 \TestPackage{fancyhdr}
+\TestPackage{filehook}
 \TestPackage{fixltx2e}
 \TestPackage{fix-cm}
 \TestPackage{float}