procd.sh: use parameterized respawn values

continue work started here: http://patchwork.ozlabs.org/patch/520859

Extend /etc/config/system with parameters to set the default respawn treshold and respawn timeout
	for procd launched services that have respawn enabled.
This results in cleaner init scripts, while making sure services have respawn parameters set.

Signed-off-by: Claudiu Brasovean <cbrasho@gmail.com>

package/system/procd/files/procd.sh

@@ -351,8 +351,10 @@ _procd_close_instance() {
 	if json_select respawn ; then
 		json_get_values respawn_vals
 		if [ -z "$respawn_vals" ]; then
+			local respawn_threshold=$(uci_get system.@service[0].respawn_threshold)
+			local respawn_timeout=$(uci_get system.@service[0].respawn_timeout)
 			local respawn_retry=$(uci_get system.@service[0].respawn_retry)
-			_procd_add_array_data 3600 5 ${respawn_retry:-5}
+			_procd_add_array_data ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
 		fi
 		json_select ..
 	fi