[spice] relocate openssl code into seperate function

This is in preperation of switching to an alternative SSL library
as OpenSSL conflicts with the GNU licence.

client/spice/rsa.h

@@ -0,0 +1,30 @@
+/*
+Looking Glass - KVM FrameRelay (KVMFR) Client
+Copyright (C) 2017 Geoffrey McRae <geoff@hostfission.com>
+https://looking-glass.hostfission.com
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <stdbool.h>
+#include <stdint.h>
+
+struct spice_password
+{
+  char         * data;
+  unsigned int   size;
+};
+
+bool spice_rsa_encrypt_password(uint8_t * pub_key, char * password, struct spice_password * result);
+void spice_rsa_free_password(struct spice_password * pass);