chkconfig.ltx: add packages used by documentation files

- check for diagbox, fp and pict2e
- the doc files uses several styles from the was package, but there is no was.sty, thus check for e.g. upgreek.sty

lib/chkconfig.ltx

@@ -367,11 +367,14 @@
 \TestPackage{braket}
 \TestPackage{cancel}
 \TestPackage{colortbl}
+\TestPackage{diagbox}
 \TestPackage{eurosym}
+\TestPackage{fp}
 \TestPackage{marginnote}
 \TestPackage{picinpar}
+\TestPackage{pict2e}
 \TestPackage{sidecap}
-\TestPackage{was}
+\TestPackage{upgreek}
 
 % psnfss is in fact the name of a set of style files, among which
 % times.sty. If times.sty is here, we will assume that everything is fine.