- Cleaned up warning-generating code

diff --git a/library/x509parse.c b/library/x509parse.c
index 378f0a9..0e410f4 100644
--- a/library/x509parse.c
+++ b/library/x509parse.c
@@ -776,7 +776,7 @@
                                        unsigned char *ns_cert_type)
 {
     int ret;
-    x509_bitstring bs = {0};
+    x509_bitstring bs = { 0, 0, NULL };
 
     if( ( ret = asn1_get_bitstring( p, end, &bs ) ) != 0 )
         return( POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS | ret );
@@ -795,7 +795,7 @@
                                unsigned char *key_usage)
 {
     int ret;
-    x509_bitstring bs = {0};
+    x509_bitstring bs = { 0, 0, NULL };
 
     if( ( ret = asn1_get_bitstring( p, end, &bs ) ) != 0 )
         return( POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS | ret );