SCRUM#419: Fix enabling family-shield bug

package/debian/changelog

+le-parental-control (0.0.2) testing; urgency=medium
+
+  * Fix enabling family-shield bug 
+
+ -- Andre Luis da Silva Machado <contato@c3sl.ufpr.br>  Thu, 01 Mar 2018 11:20:02 -0200
+
 le-parental-control (0.0.1) testing; urgency=medium
 
   * Separate family-shield and le-conf

package/family-shield

@@ -54,7 +54,7 @@ function enable_family() {
         service network-manager restart
         message="Family Shield enabled"
     elif [[ $(check_status) -eq 2 ]]; then                  # insert line
-        sed "s/$pivot_line/$pivot_line\n$domainsupersede/" $dhcp_file
+        sed -i "s/$pivot_line/$pivot_line\n$domainsupersede/" $dhcp_file
         service network-manager restart
         message="Family Shield enabled"
     fi