Don’t suggest using sendmail’s -f flag.
Don’t suggest using sendmail’s -f flag.

This flag seems to be different depending on which program you have
installed as sendmail, so let’s remove it for now and carefully examine
the situation in case this change breaks anyone.

fixes #13

anthonyfok/dh-make-golang,Debian/dh-make-golang,anthonyfok/dh-make-golang,Debian/dh-make-golang