Reload sysctl

This patch add sysctl.conf reload command so that bridge-nf-call-* settings gets
loaded and security groups are functional without rebooting.

Change-Id: I6ad08c682cf11f760e8fa1cd7bf4a02dbf0bf0a0
Fixes: rhbz#1104619
(cherry picked from commit bb39f0ce5e11e2f72954289db059be961491f253)