download.mk: use HTTPS for git.lede-project.org

Some Git versions have issues following the HTTP->HTTPS redirect and since
the keyring package is fetched from this host, switching to HTTPS is a
sensible choice anyway.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

include/download.mk

@@ -7,7 +7,7 @@
 #
 
 OPENWRT_GIT = http://git.openwrt.org
-LEDE_GIT = http://git.lede-project.org
+LEDE_GIT = https://git.lede-project.org
 
 DOWNLOAD_RDEP=$(STAMP_PREPARED) $(HOST_STAMP_PREPARED)