Use neutron security groups in BigSwitch plugin

Configures the Big Switch third-party plugin to
use neutron security groups instead of nova
security groups.

Change-Id: I6bc3046ff0e70b8288a7c3f3d6f975376adc081a
Implements: blueprint bigswitch-neutron-security
Use sahara.conf.sample instead of old one

Sahara internals was updated, now we can use correct conf sample.

Change-Id: Ia8d99c2742785c3b5c724617a5dfc2880624a03f
Set IRONIC_VM_SPECS_RAM to 512 by default

Fix insufficient amount of RAM provided for fake baremetal nodes

Change-Id: I87d04a23a28dcb03dfdaf3c6cfad96cf2bda2516
Disable ceilometer's swift middleware

This middleware is spamming rsyslog with rabbitmq debug logs, making
this middleware practically unusable in combination with rsyslog. Because of
this, the rsyslog logs now account for 35% percent of the logs we store
in logstash. Until the underlying problem is solved disable the
offending code.

Change-Id: I50a73ae6beb1a11c41225340779fe8d7a1081e46
Related-Bug: #1294789
Merge "Set IRONIC_VM_SPECS_RAM to 512 by default"
Merge "Use neutron security groups in BigSwitch plugin"
Merge "Use sahara.conf.sample instead of old one"
Merge branch 'master' of github.com:openstack-dev/devstack