Fix crypto to be compatible with other systems.
Fix crypto to be compatible with other systems.

  While writing the php crypto routines, I discovered that it and fedmsg's
  crypto routine were producing different signatures.  I assumed php was wrong
  and worked at it for a while until I was contradicted.

  This updates fedmsg.crypto.sign to produce the same signature as php's crypto
  module and the following shell command:

    echo -n "foo" | openssl dgst -sign private_keys/test_cert.pem | base64

cicku/fedmsg,cicku/fedmsg,cicku/fedmsg,mathstuf/fedmsg,mathstuf/fedmsg,pombredanne/fedmsg,maxamillion/fedmsg,vivekanand1101/fedmsg,fedora-infra/fedmsg,vivekanand1101/fedmsg,chaiku/fedmsg,fedora-infra/fedmsg,fedora-infra/fedmsg,mathstuf/fedmsg,pombredanne/fedmsg,maxamillion/fedmsg,pombredanne/fedmsg,chaiku/fedmsg,chaiku/fedmsg,vivekanand1101/fedmsg,maxamillion/fedmsg