[xmlsec] bugfixes for mscrypto support

[Aleksey Sanin]

>With this patch all tests that should work since the code for that is
>implemenetd, are working on my system. Since private key import is not
>supported a lot of the encryption tests still fail. However implementing
>plain private key node import just for these tests is not of anyones
>interest, so I'm afraid that will stay like this, or the testsuite
>should be altered.
>
Any suggestion on how to do that? I thought that current scheme is 
pretty general:
we use pkcs12 files to import keys and thought that MSCrypto can load 
these keys.

>Aleksey: could you plz apply the patch, and commit the files? :)
>  
>
Done. The patch applied and commited. However, after applying that patch 
I could not
execute tests with mscrypto anymore because the test suite freezes on 
the first DSig test.
I have not investigated the issue yet but it seems strange because the 
patch does not look
dangerous.


Aleksey