exclude EMACS support in a2ps because of build failures

[boegel]

merging in ater verifying this fixes problems like:

2922 make[3]: Entering directory `/tmp/easybuild_build/a2ps/4.14/goalf-1.1.0-no-OFED/a2ps-4.14/contrib/emacs'
2923 WARNING: Warnings can be ignored. :-)
2924 if test "emacs" != no; then \
2925       set x; \
2926       list='a2ps.el a2ps-print.el'; for p in $list; do \
2927         if test -f "$p"; then d=; else d="./"; fi; \
2928         set x "$@" "$d$p"; shift; \
2929       done; \
2930       shift; \
2931       EMACS="emacs" /bin/sh ../../auxdir/elisp-comp "$@" || exit 1; \
2932     else : ; fi
2933 Loading /usr/share/emacs/site-lisp/site-start.d/igrep-init.el (source)...
2934 Loading /usr/share/emacs/site-lisp/site-start.d/lang-coding-systems-init.el (source)...
2935 Wrong type argument: stringp, nil

Note: the problem only manifested itself when the a2ps builds were submitted as a job, not when the build is performed via an interactive shell...