New function ASN1_STRING_clear_free which cleanses an ASN1_STRING
structure before freeing it.
Call ASN1_STRING_clear_free on PKCS#8 private key components.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit a8ae0891d4)
The stuff in here is based on patches supplied to me by Steven Schoch <schoch@sheba.arc.nasa.gov> to do DSS. I have since modified a them a little but a debt of gratitude is due for doing the initial work.