Have the NSM deny all non-validating connections non-interactively

* net/nsm.el (nsm-query): If running non-interactively, then say
`no' to everything.
Export running_asynch_code to Lisp

* lisp.h: Remove "extern bool running_asynch_code".

* emacs.c (syms_of_emacs): Export running_asynch_code to Lisp so
that functions can tell what context they are being run under.
(nsm-query): Also make asynch code say `no' to everything.