should we add "setresult" to older powerman device files

[chu11]

With setresult soon to be merged (#168) there's a question if it should be used in older device files, notably redfishpower and ipmipower device files.

pro: it'll offer folks behavior that is more in line with what they are expecting

con: it breaks old behavior, especially device files that have been around for like 20 years

[chu11]

or alternately, we create new device files like ipmipower_errorhandling.dev or whatever