ASN1_STRING cleanup - realloc has handled NULL since I had a mullet

ASN1_STRING cleanup - realloc has handled NULL since I had a mullet
and parachute pants - and since it's obvious there is no guarantee
the caller doesn't pass in the data area in the argument, use memmove
instead of memcpy so overlapping areas are handled correctly.
 Also, pointers can be usefully printed in hex with %p, in error messaeges
rather than the bizzaro stuff that was there using mystical buffer lengths
and abuse of strlcpy-converted-blindly-from-strcpy