dnsmasq: Fix parameter 'limit'

'limit' is actually the number of IP addresses to serve. See the use of ipcalc.sh.
For getting the expected number of IP addresses served, we have to decrement
limit by one.

Patch from: kentarou matsuyama <matsuyama@thinktube.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@25100 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/dnsmasq/files/dnsmasq.init

@@ -300,6 +300,7 @@ dhcp_add() {
 	leasetime="${leasetime:-12h}"
 	start="$(dhcp_calc "${start:-100}")"
 	limit="${limit:-150}"
+	[ "$limit" -gt 0 ] && limit=$((limit-1))
 	eval "$(ipcalc.sh $ipaddr $netmask $start $limit)"
 	if [ "$dynamicdhcp" = "0" ]; then END="static"; fi
 	append args "--dhcp-range=$networkid,$START,$END,$NETMASK,$leasetime${options:+ $options}"