IPMI SOL activate verification logic update

The current logic checks for "Petitboot" on the IPMI SOL output. Most
of the time we see the SOL output wraps up during the boot in progress
and it couldn't find the string when looked up.

The new logic breaks down into two pieces. First, it checks for the
welcome message on the SOL as the marker for host boot in progress and
secondly, checks for the "ISTEP".

This two prong approach achieves:
1. SOL active verification is faster and
2. Better strings validation SOL message.

Resolves  openbmc/openbmc-test-automation#1019

Change-Id: I94e8c64a70bf20dd34d6669c79cfa4db2b2550f2
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
1 file changed