Revert 3264 combo build back to warning (backout 7061112), warning to be parsed by RE.

Revert 3264 combo build back to warning (backout 7061112), warning to be parsed by RE.

RE has implemented code for windows-i586 builds to parse and wait for up to three hours for the windows-amd64 build to complete, and then rerun the 3264 combo installer target. If the three hours is exceeded, RE will present a hard failure.

By reverting to a warning on the combo installer, it's possible to recover from a failed combo installer by just rerunning the target post windows-i586 build. Still should be a rare occurance, only happening for a hard failure on windows-amd64.