patman: Make dry-run output match real functionality

When run with the --dry-run argument patman prints out information
showing what it would do.  This information currently doesn't line up
with what patman/git send-email really do.  Some basic examples:
- If an email address is addressed via "Series-cc" and "Patch-cc" patman
  shows that email address would be CC-ed two times.
- If an email address is addressed via "Series-to" and "Patch-cc" patman
  shows that email address would be sent TO and CC-ed.
- If an email address is addressed from a combination of tag aliases,
  get_maintainer.pl output, "Series-cc", "Patch-cc", etc patman shows
  that the email address would be CC-ed multiple times.

Patman currently does try to send duplicate emails like the --dry-run
output shows, but "git send-email" intelligently removes duplicate
addresses so this patch shouldn't change the non-dry-run functionality.

Change patman's output and email addressing to line up with the
"git send-email" logic.  This trims down patman's dry-run output and
prevents confusion about what patman will do when emails are actually
sent.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>