BUILD: fd: include log.h from fd.c

It's needed for ha_alert() and the header was missing.
diff --git a/src/fd.c b/src/fd.c
index 6362225..733658c 100644
--- a/src/fd.c
+++ b/src/fd.c
@@ -91,6 +91,7 @@
 #include <haproxy/cfgparse.h>
 #include <haproxy/fd.h>
 #include <haproxy/global.h>
+#include <haproxy/log.h>
 #include <haproxy/port_range.h>
 #include <haproxy/tools.h>