dhcp: enable gentle shutdown

For now, `systemctl stop dhcpd' cannot stop dhcpd correctly, the SIGTERM
signal would time out, causing a SIGKILL signal sent to dhcpd.

Patch site.h to enable gentle shutdown to so that dhcpd could be stopped
by SIGTERM.

(From OE-Core rev: 2c789bac353e17637549a7b31706761ba848728e)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-connectivity/dhcp/dhcp/0001-site.h-enable-gentle-shutdown.patch

@@ -0,0 +1,25 @@
+Upstream-Status: Inappropriate [configuration]
+
+Subject: [PATCH] site.h: enable gentle shutdown
+
+Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
+---
+ includes/site.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/includes/site.h b/includes/site.h
+index 73fa4e8..9c33de3 100644
+--- a/includes/site.h
++++ b/includes/site.h
+@@ -280,7 +280,7 @@
+    situations.  We plan to revisit this feature and may
+    make non-backwards compatible changes including the
+    removal of this define.  Use at your own risk.  */
+-/* #define ENABLE_GENTLE_SHUTDOWN */
++#define ENABLE_GENTLE_SHUTDOWN
+ 
+ /* Include old error codes.  This is provided in case you
+    are building an external program similar to omshell for
+-- 
+1.9.1
+

meta/recipes-connectivity/dhcp/dhcp_4.3.3.bb

@@ -7,6 +7,7 @@ SRC_URI += "file://dhcp-3.0.3-dhclient-dbus.patch;striplevel=0 \
             file://dhclient-script-drop-resolv.conf.dhclient.patch \
             file://replace-ifconfig-route.patch \
             file://CVE-2015-8605.patch \
+            file://0001-site.h-enable-gentle-shutdown.patch \
            "
 
 SRC_URI[md5sum] = "c5577b09c9017cdd319a11ff6364268e"