[xmlsec] Initialize IV for AES-CBC mode

[Aleksey Sanin]

There is no interface to set IV vector by application. It is generated
and set into EVP context in the xmlSecOpenSSLEvpBlockCipherCtxInit()
function (search for "ctx->iv" string):

http://cvs.gnome.org/viewcvs/xmlsec/src/openssl/ciphers.c?view=markup


Aleksey