[xmlsec] NSS changes corresponding to Roumen's changes

[Aleksey Sanin]

Tej

Thanks for the patch! I have applied and commited it with a couple
changes (see bellow). Unfotrunately, this patch did not make it in
1.1.0 release which should happen for tommorow :(
I am closing the bug about X509Data node templates with a reference
to remaining bug about ASN1 integers in xmlsec-nss

Aleksey

My changes:
--------------------------------------------------------------------------------------------

0) I moved the common code that determines the X509Data node
content into a separate function in xmlsec-core. I think it's slightly
better from code maintainance point of view :) Also I have updated
xmlsec-openssl to use this code as well.

1) xmlSecNssX509NameWrite() function
Seems like there is an unnecessary strcpy in this function:

   res = xmlCharStrdup(str);
   if(res == NULL) {
        ...
   }
   strcpy((char *)res, (const char *)str);

I've replaced this with
   res = xmlStrdup(BAD_CAST str);
   if(res == NULL) {
        ...
   }