test-lib.sh: "tidied" emacs_deliver_message ()

Added initialization and checking of smtp_dummy_port
like it was done with smtp_dummy_pid.

Made those function-local variables.

One 8 spaces to tab consistency conversion.

And last, but definitely not least; while doing above
noticed that there were quite a few double-quoted strings
where $@ was in the middle of it -- replaced those with $*
for robustness ("...$@..." expands params to separate words,
"...$*..." params expands to single word).