stubs: buildfix

The new stubs for httpd and ioutil gave errors like:

  ioutil_stubs.c: In function ‘ioutil_init’:
  ioutil_stubs.c:27: error: implicit declaration of function ‘LOG_DEBUG’
  ioutil_stubs.c:28: error: ‘ERROR_OK’ undeclared (first use in this function)
  ioutil_stubs.c:28: error: (Each undeclared identifier is reported only once
  ioutil_stubs.c:28: error: for each function it appears in.)

Fix.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/helper/ioutil_stubs.c

@@ -21,6 +21,7 @@
 #include <config.h>
 #endif
 #include "ioutil.h"
+#include "log.h"
 
 int ioutil_init(struct command_context *cmd_ctx)
 {

src/server/httpd_stubs.c

@@ -21,6 +21,7 @@
 #include <config.h>
 #endif
 #include "httpd.h"
+#include "log.h"
 
 int httpd_start(struct command_context *cmd_ctx)
 {