Skip asn1 zeroize if freeing shallow pointers

This skips zeroizing additional pointers to data.
(Note: actual sensitive data should still be zeroized when freed.)

Signed-off-by: Glenn Strauss <gstrauss@gluelogic.com>
diff --git a/library/asn1parse.c b/library/asn1parse.c
index 12a378c..4bc1771 100644
--- a/library/asn1parse.c
+++ b/library/asn1parse.c
@@ -314,7 +314,6 @@
     while( seq != NULL )
     {
         mbedtls_asn1_sequence *next = seq->next;
-        mbedtls_platform_zeroize( seq, sizeof( *seq ) );
         mbedtls_free( seq );
         seq = next;
     }
@@ -450,7 +449,8 @@
     while( ( cur = *head ) != NULL )
     {
         *head = cur->next;
-        mbedtls_asn1_free_named_data( cur );
+        mbedtls_free( cur->oid.p );
+        mbedtls_free( cur->val.p );
         mbedtls_free( cur );
     }
 }
@@ -460,7 +460,6 @@
     for( mbedtls_asn1_named_data *next; name != NULL; name = next )
     {
         next = name->next;
-        mbedtls_platform_zeroize( name, sizeof( *name ) );
         mbedtls_free( name );
     }
 }