dispatcher.d/12-dhcpd: use reset-failed command

Suggested by Lukas Nykryn.

12-dhcpd

@@ -10,8 +10,10 @@ if [ "$STATUS" = "up" ]; then
     # time-out for dispatcher script is 3s (rhbz#1003695#8)
     sleep 2
     # restart the services
-    systemctl -q is-enabled dhcpd.service && systemctl restart dhcpd.service
-    systemctl -q is-enabled dhcpd6.service && systemctl restart dhcpd6.service
+    # In case this dispatcher script is called several times in a short period of time, it might happen that
+    # systemd refuses to further restart the units. Therefore we use reset-failed command to prevent it.
+    systemctl -q is-enabled dhcpd.service && systemctl restart dhcpd.service && systemctl reset-failed dhcpd.service
+    systemctl -q is-enabled dhcpd6.service && systemctl restart dhcpd6.service && systemctl reset-failed dhcpd6.service
 fi
 
 exit 0

dhcp.spec

@@ -18,7 +18,7 @@
 Summary:  Dynamic host configuration protocol software
 Name:     dhcp
 Version:  4.3.3
-Release:  7%{?dist}
+Release:  8%{?dist}
 # NEVER CHANGE THE EPOCH on this package.  The previous maintainer (prior to
 # dcantrell maintaining the package) made incorrect use of the epoch and
 # that's why it is at 12 now.  It should have never been used, but it was.
@@ -663,6 +663,9 @@ done
 %doc doc/html/
 
 %changelog
+* Tue Nov 24 2015 Jiri Popelka <jpopelka@redhat.com> - 12:4.3.3-8
+- dispatcher.d/12-dhcpd: use reset-failed command
+
 * Mon Nov 23 2015 Jiri Popelka <jpopelka@redhat.com> - 12:4.3.3-7
 - dhclient-script: hostname -> hostnamectl --transient