credentials_tls: Keep thumbprint rather than client certificate

By storing the client certificate the certificate became detached from
its private key stored in user certificate store. This rendered client
certificates useless for client TLS authentication.

Now, the client certificate thumbprint is stored instead. The client
certificate is looked up in the user certificate store as required.

This breaks profile XML and BLOB backward compatibility. Since the
client certificate support was broken, nobody probably used those in
the settings before.

Signed-off-by: Simon Rozman <simon@rozman.si>

lib/TLS/include/Credentials.h

@@ -142,12 +142,7 @@ namespace eap
             _In_opt_z_       LPCTSTR       pszTargetName);
 
     public:
-        winstd::cert_context m_cert;                ///< Client certificate
-
-    private:
-        /// \cond internal
-        static const unsigned char s_entropy[1024];
-        /// \endcond
+        std::vector<unsigned char> m_cert_hash; ///< Client certificate SHA-1 thumbprint
     };
 
     /// @}