pause-tube should check tube name is ok
pause-tube should check tube name is ok

This change updates pause-tube to return BAD_FORMAT when an
invalid tube name is supplied. At present pause-tube will return
NOT_FOUND after it fails to find an invalid tube.

This is more of a consistency thing than a bug, per se.

mickeyouyou/beanstalkd,kr/beanstalkd,potatosalad/beanstalkd,wfxiang08/beanstalkd,bmhatfield/beanstalkd,mickeyouyou/beanstalkd,kr/beanstalkd,bmhatfield/beanstalkd,tdg5/beanstalkd,wfxiang08/beanstalkd,potatosalad/beanstalkd,ifduyue/beanstalkd,tdg5/beanstalkd,ifduyue/beanstalkd