ds-lite: drop default encaplimit value

Setting encaplimit to a numerical value results into the value being
included as tunnel encapsulation limit in the destination option header
for tunneled packets.
Several users have reported interop issues as not all ISPs support the
destination option header containing the tunnel encapsulation limit
resulting into broken ds-lite connectivity.
Therefore drop the default encaplimit value for ds-lite tunnels so
no destination option header is included by default.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
(backported from 1241707b40)

package/network/ipv6/ds-lite/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ds-lite
 PKG_VERSION:=7
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 PKG_LICENSE:=GPL-2.0
 
 include $(INCLUDE_DIR)/package.mk

package/network/ipv6/ds-lite/files/dslite.sh

@@ -69,7 +69,7 @@ proto_dslite_setup() {
 	json_add_string remote "$peeraddr"
 	[ -n "$tunlink" ] && json_add_string link "$tunlink"
 	json_add_object "data"
-	  json_add_string encaplimit "${encaplimit:-4}"
+	  [ -n "$encaplimit" ] && json_add_string encaplimit "$encaplimit"
 	json_close_object
 	proto_close_tunnel