Build the required error log header file for elogs

Take the elog.yaml file and generate the required hpp
file required for build time validation and error log
processing.

A future commit will delete elog-gen.hpp and will
start dynamically generating it during build.

Change-Id: I21a87d959096a2541de69fde47f57f02482a00cc
Signed-off-by: Andrew Geissler <andrewg@us.ibm.com>
6 files changed