memory: add missing curl_printf header

ftp_send_command() was using vsnprintf() without including the libcurl
*rintf() replacement header. Fix by including curl_printf.h and also
add curl_memory.h while at it since memdebug.h depends on it.

Closes #2999
Reviewed-by: Daniel Stenberg <daniel@haxx.se>

lib/security.c

@@ -61,7 +61,9 @@
 #include "strcase.h"
 #include "warnless.h"
 #include "strdup.h"
-/* The last #include file should be: */
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
 #include "memdebug.h"
 
 static const struct {