Adding Nagios Support

This commit adds an option to install Nagios to monitor the
openstack components. Initially we are only monitoring a small
subset of what could eventually be monitored
http://bugzilla.redhat.com/show_bug.cgi?id=912768

Change-Id: I176876e5ecc35e7c58ef49534341939fd7998701
Add configuration options for CPU and RAM overcommitment

By default, overcommitment is enabled and set to 16.0 and 1.5 for
CPU and RAM, respectively. In many situations, those values are too
high or overcomittment needs to be disabled (by setting the options
to 1.0) completely. Also, by default the CoreFilter is not enabled.

Change-Id: I08b414a1fa6e596747be51608d8d0bbeb2a619fe
Merge "Adding Nagios Support" into folsom
Merge "Add configuration options for CPU and RAM overcommitment" into folsom