simplify getOpType by using Enum's static function valueOf
made kill command be more polite
refactor according to comments
remove getOpType
Merge pull request #479 from dcapwell/nicekill

made kill command be more polite
Merge pull request #478 from shimingfei/simplifyGetOpType

simplify getOpType by using Enum's static function valueOf
Add suppress rule for Tachyon *Conf classes to exempt the public final members as all upper cases.