[xmlsec] xmlsec tests use private keys in the clear

[Wan-Teh Chang]

Aleksey Sanin wrote:

 > I would be really surprised if NSS has no way
 > to import private key in the keys db.

NSS has no way to import a private key in the clear.
The private key (outside the NSS boundary) must be
properly encrypted.  This is intentional to force
good key hygiene.

Wan-Teh