BUILD: makefile: fix the "make clean" target on strict bourne shells

As reported by @axinojolais in issue #1217, some older bourne shells do
not expand on braces so some files were not cleaned since the recent
splitting of the contrib/ subdir. Let's fix that by explicitly listing
the patterns to be cleared (which are in much smaller quantity now that
contrib was removed), and for grouping them with their respective dirs.

At some point, some recursive makefiles would probably help there.
diff --git a/Makefile b/Makefile
index d38d6c6..c39fac6 100644
--- a/Makefile
+++ b/Makefile
@@ -1008,13 +1008,14 @@
 	$(Q)for dir in . src dev/* admin/* addons/* include/* doc; do rm -f $$dir/*~ $$dir/*.rej $$dir/core; done
 	$(Q)rm -f haproxy-$(VERSION).tar.gz haproxy-$(VERSION)$(SUBVERS)$(EXTRAVERSION).tar.gz
 	$(Q)rm -f haproxy-$(VERSION) haproxy-$(VERSION)$(SUBVERS)$(EXTRAVERSION) nohup.out gmon.out
-	$(Q)rm -f {admin,dev}/*/*.[oas] {admin,dev}/*/*/*.[oas] {admin,dev}/*/*/*/*.[oas]
 	$(Q)rm -f addons/promex/*.[oas]
 	$(Q)rm -f addons/51degrees/*.[oas] addons/51degrees/dummy/*.[oas] addons/51degrees/dummy/*/*.[oas]
 	$(Q)rm -f addons/deviceatlas/*.[oas] addons/deviceatlas/dummy/*.[oas]
 	$(Q)rm -f addons/ot/src/*.[oas]
 	$(Q)rm -f addons/wurfl/*.[oas] addons/wurfl/dummy/*.[oas]
+	$(Q)rm -f admin/*/*.[oas] admin/*/*/*.[oas]
 	$(Q)rm -f admin/iprange/iprange admin/iprange/ip6range admin/halog/halog
+	$(Q)rm -f dev/*/*.[oas]
 	$(Q)rm -f dev/flags/flags dev/poll/poll dev/tcploop/tcploop
 	$(Q)rm -f dev/hpack/decode dev/hpack/gen-enc dev/hpack/gen-rht