zero out content of all krb5_free_x_content like functions to make sure data doesnt get reused, idea from Wynn Wilkes <wwilkes@vintela.com>

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@15167 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/krb5/context.c

@@ -266,6 +266,7 @@ krb5_free_context(krb5_context context)
 	HEIMDAL_MUTEX_destroy(context->mutex);
 	free(context->mutex);
     }
+    memset(context, 0, sizeof(*context));
     free(context);
 }