package/iputils: bump version to 31d947cf7156cf78d3f57e0bd82b33e6f6ece6b4

Includes a fix for static builds using libgcrypt.

Fixes:
 http://autobuild.buildroot.net/results/55a7db5c0cbc34bbf6a2cbc52713d8822deec5b2
 http://autobuild.buildroot.net/results/864d8901eb901182ce186cf9a845636040e242bb
 http://autobuild.buildroot.net/results/aba522aa164267993fb1f1bbc57733be0cbea680

Signed-off-by: Martin Bark <martin@barkynet.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/iputils/iputils.hash

@@ -1,2 +1,2 @@
 # Locally computed
-sha256	73de246aee1fd3cd69b1341a0c4e1b4acfa655fe6f7363fd9424824aa8bf5a57	iputils-3a86a2542c6fe29413c439bebeae11ec8a57ec7c.tar.gz
+sha256	08b9f686fcc874f75b465f90f3e831aa9ac1f2e043f4bb61e6d99868e8869025	iputils-31d947cf7156cf78d3f57e0bd82b33e6f6ece6b4.tar.gz

package/iputils/iputils.mk

@@ -11,7 +11,7 @@
 # and IPv6 updates.
 # http://www.spinics.net/lists/netdev/msg279881.html
 
-IPUTILS_VERSION = 3a86a2542c6fe29413c439bebeae11ec8a57ec7c
+IPUTILS_VERSION = 31d947cf7156cf78d3f57e0bd82b33e6f6ece6b4
 IPUTILS_SITE = $(call github,iputils,iputils,$(IPUTILS_VERSION))
 IPUTILS_LICENSE = GPLv2+, BSD-3c, BSD-4c
 # Only includes a license file for BSD