Currently when using "fedpkg commit -c" the git message gets merged together and "git format-patch" creates weird subjects that get merged into one line.

This patch changes clog behaviour to play nicer with git:
- take first line, strip dashes (like before), add empty line after it
- take rest of the lines, leave dashes to form bullet list of items changed

This creates nicer history that is more likely to fit within 80 character line