merged from protocol 4 branch; fix for DFL-618, The ?debug query string does not follow along when switching between dragonfly versions
merged from protocol 4 branch; fix for DFL-618, The ?debug query string does not follow along when switching between dragonfly versions

runeh/dragonfly-stp-1,runeh/dragonfly-stp-1,runeh/dragonfly-stp-1