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).