script_parser: Fix fread to return number of bytes read

script_parser: Fix fread to return number of bytes read

From fread man page:

The function fread() reads nmemb elements of data, each size bytes
long, from the stream pointed to by stream, storing them at the
location given by ptr.

If size is something else than 1, the return value is not number of
bytes read. The intention here is to have it return number of bytes so
that the debug print can print it correctly.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@iki.fi>