gpgscm: Fix installation of error handler.

* tests/gpgscm/ffi.scm: Set '*error-hook*' again so that the
interpreter will use our function.

Signed-off-by: Justus Winter <justus@g10code.com>

tests/gpgscm/ffi.scm

@@ -61,6 +61,7 @@
     (_exit (cadr x)))
    (else
     (apply error x))))
+(set! *error-hook* throw)
 
 ;; Terminate the process returning STATUS to the parent.
 (define (exit status)