contrib/cfengine-code-style.el: Fix file header and footer lines for ELPA compatibility

- Fix header line
- Add footer line
- Add Commentary section
- Add Code section
- Change semicolons of header comment lines from three to two
Merge pull request #1172 from yasuyk/fix-for-elpa

contrib/cfengine-code-style.el: Fix file header and footer lines for ELPA compatibility