Comment 1 for bug 1427893

Current defaults on Ubuntu 14.04.01

``` bash
root@578134-compute07:~# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04.1 LTS"

root@578134-compute07:~# uname -a
Linux 578134-compute07 3.16.0-34-generic #47~14.04.1-Ubuntu SMP Fri Apr 10 17:49:16 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

root@578134-compute07:~# sysctl -a | grep gc_thre
net.ipv4.neigh.default.gc_thresh1 = 128
net.ipv4.neigh.default.gc_thresh2 = 512
net.ipv4.neigh.default.gc_thresh3 = 1024
net.ipv4.route.gc_thresh = -1
net.ipv4.xfrm4_gc_thresh = 32768
net.ipv6.neigh.default.gc_thresh1 = 128
net.ipv6.neigh.default.gc_thresh2 = 512
net.ipv6.neigh.default.gc_thresh3 = 1024
net.ipv6.route.gc_thresh = 1024
net.ipv6.xfrm6_gc_thresh = 32768
```