Fix: libcrmcommon,pengine,tools: pass local node name to resource agents

Preivously, crm_node -n would show the local uname on remote nodes, even when
the node name known to the cluster was different. Now, the policy engine adds
environment variables with the local node name and UUID before calling the
resource agent. If crm_node detects these variables, it will use them instead
of uname.

This only affects crm_node behavior when called via the cluster, not
directly from the command line.

Based on patch originally provided by Andrew Beekhof <andrew@beekhof.net>