lisa.tests.base: Improvde DmestTestConf help
lisa.tests.base: Improvde DmestTestConf help

Make it clearer that the regex only matches the content of the message,
not the header part consisting in facility, timestamp and subsystem.

ARM-software/lisa,credp/lisa,credp/lisa,ARM-software/lisa,credp/lisa,ARM-software/lisa,ARM-software/lisa,credp/lisa