Installation guide

Resolves: #571557
Adds note on managing virtual machines in a cluster.
Resolves: #742310
Documents new privilege level parameter for IPMI fence device.
Resolves: #747456
Corrects small typographical errors throughout document.
Resolves: #748935
Clarifies description of iptables firewall filters.
Resolves: #718084
Provides link to Support Essentials article.
Resolves: #749858
Documents support for RHEV-M REST API fence agent.
Resolves: #569585
Clarifies support statement for running Samba in a cluster.
Revisio n 6 .0- 1 Th u Ju l 21 2011 St even Levin e
Revision Hist o ry
131