CLEANUP: includes: fix includes for a number of users of fd.h
It appears that fd.h includes a number of unneeded files and was
included from standard.h, and as such served as an intermediary
to provide almost everything to everyone.
By removing its useless includes, a long dependency chain broke
but could easily be fixed.
diff --git a/src/session.c b/src/session.c
index c4323da..3c47937 100644
--- a/src/session.c
+++ b/src/session.c
@@ -28,6 +28,7 @@
#include <proto/checks.h>
#include <proto/connection.h>
#include <proto/dumpstats.h>
+#include <proto/fd.h>
#include <proto/freq_ctr.h>
#include <proto/frontend.h>
#include <proto/hdr_idx.h>