download: get rid of trailing slash removal hack for FOO_SITE

Not needed anymore since the URLs have been cleared, the manual states
they are illegal and a check has been introduced to notice future
mistakes.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/pkg-generic.mk

@@ -388,7 +388,7 @@ endif
 $(2)_ALL_DOWNLOADS = \
 	$$(foreach p,$$($(2)_SOURCE) $$($(2)_PATCH) $$($(2)_EXTRA_DOWNLOADS),\
 		$$(if $$(findstring ://,$$(p)),$$(p),\
-			$$($(2)_SITE:/=)/$$(p)))
+			$$($(2)_SITE)/$$(p)))
 
 ifndef $(2)_SITE
  ifdef $(3)_SITE