BUILD: task: remove unused includes from task.c

freq_ctr.h and time.h are not used, let's drop them.
diff --git a/src/task.c b/src/task.c
index 6763327..283d507 100644
--- a/src/task.c
+++ b/src/task.c
@@ -18,12 +18,10 @@
 #include <haproxy/api.h>
 #include <haproxy/cfgparse.h>
 #include <haproxy/fd.h>
-#include <haproxy/freq_ctr.h>
 #include <haproxy/list.h>
 #include <haproxy/pool.h>
 #include <haproxy/stream.h>
 #include <haproxy/task.h>
-#include <haproxy/time.h>
 #include <haproxy/tools.h>