- First replacement of xyssl by polarssl where needed

diff --git a/programs/pkey/mpi_demo.c b/programs/pkey/mpi_demo.c
index 699fa5a..87737c8 100644
--- a/programs/pkey/mpi_demo.c
+++ b/programs/pkey/mpi_demo.c
@@ -24,7 +24,7 @@
 
 #include <stdio.h>
 
-#include "xyssl/bignum.h"
+#include "polarssl/bignum.h"
 
 int main( void )
 {