ay UnruffledSenator UrgesMore DisciplineWASHINGTON (UPI) - Sen. Joseph S. Clark’s new charge that the “Senate establishment” is staging a sit-down strike against major Kennedy legislation left the targets ot his attack unruffled today.Senate GOP Leader Everett M. Dirksen, 111., said he thought the Pennsylvania Democrat’s attack on key committee chairmen and other sena-consideration of the tax cut 1 and to force the State-Justi Commence appropriations 1 from committee. Sen. Carl H den, D-Ariz., is chairman of appropriatons committee He said he would introduci similar resolution to force civil rights bill from the diciary committee, headed Sen. James 0. Eastland, Miss., if administration back