opkg: work around unconditional libopenssl build dependency

As the OpenWrt build system only resolves build dependencies per directory,
all opkg variants were causing libopenssl to be downloaded and built,
not only opkg-smime. Fix this by applying the same workaround as in
ustream-ssl.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

SVN-Revision: 46850

package/system/opkg/Makefile

@@ -72,7 +72,7 @@ endef
 define Package/opkg-smime
   $(call Package/opkg/Default)
   TITLE+= (with S/MIME signature support)
-  DEPENDS+=+libopenssl
+  DEPENDS+=+PACKAGE_opkg-smime:libopenssl
   VARIANT:=smime
 endef