[mle] remove memset from DelayedResponseHeader constructors (#4195)
[mle] remove memset from DelayedResponseHeader constructors (#4195)

jwhui/openthread,bukepo/openthread,abtink/openthread,chshu/openthread,openthread/openthread,librasungirl/openthread,librasungirl/openthread,jwhui/openthread,jwhui/openthread,jwhui/openthread,chshu/openthread,abtink/openthread,abtink/openthread,openthread/openthread,chshu/openthread,lanyuwen/openthread,lanyuwen/openthread,openthread/openthread,abtink/openthread,lanyuwen/openthread,bukepo/openthread,librasungirl/openthread,srickardti/openthread,lanyuwen/openthread,srickardti/openthread,chshu/openthread,librasungirl/openthread,chshu/openthread,bukepo/openthread,srickardti/openthread,srickardti/openthread,chshu/openthread,lanyuwen/openthread,lanyuwen/openthread,openthread/openthread,bukepo/openthread