msva-query-agent only append newline to msg output if tty

msva-query-agent only append newline to msg output if tty

msva-query-agent will now only append a newline to the msva return
message on stdout if there is a TTY.  This allows calling processes
that would like to capture the stdout to not have to deal with the
newline, which is not actually a part of the original message anyway.