Rename 'entity' to 'component'
Rename 'entity' to 'component'

IPMI carries a connotation of what an 'entity' is.  While
sticking strictly to the nomenclature of 'sensor' that actually
maps would be misleading, entity is also confusing.  Renaming
the element to be 'component' to express what it tends to represent
without getting confused with the IPMI concept of 'entity'.

Change-Id: I592e1e6b9588bf381588c7d9d3e6531eb277d23c

openstack/pyghmi,stackforge/pyghmi,benoit-canet/pyghmi,openstack/pyghmi