#1502 saHpiGetChildEntityPath incorrectly handles root entity

[Anton Pak]

File: openhpid/safhpi.c
Function: saHpiGetChildEntityPath

Before looking in Domain Entity Tree this function checks existence of entity specified by ParentEntityPath parameter.
This check fails for {ROOT, 0} entity and function returns INVALID_DATA.
Apparently it is not correct.
Base HPI Spec says:

-------------
To retrieve the entire Domain Entity Tree, an HPI User can start by calling this function with an entity path containing only { { SAHPI_ROOT, 0 } } to retrieve children of the root node, then calling the function recursively for each of those children, and so forth.
-------------

[Anton Pak]

Fixed in trunk (rev #7056)