CLEANUP: include: tree-wide alphabetical sort of include files

This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
diff --git a/src/buffer.c b/src/buffer.c
index e0db429..0b3b69c 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -16,11 +16,10 @@
 
 #include <haproxy/api.h>
 #include <haproxy/dynbuf.h>
+#include <haproxy/global.h>
 #include <haproxy/list.h>
 #include <haproxy/pool.h>
 
-#include <haproxy/global.h>
-
 struct pool_head *pool_head_buffer;
 
 /* list of objects waiting for at least one buffer */