Removed executable bits for some maps

Stumpled upon strange rpmlint errors when updating the openSUSE games package

```
openra.noarch: W: script-without-shebang /usr/share/openra/mods/cnc/maps/the-hot-box/map.yaml
This text file has executable bits set or is located in a path dedicated for
executables, but lacks a shebang and cannot thus be executed.  If the file is
meant to be an executable script, add the shebang, otherwise remove the
executable bits or move the file elsewhere.

openra.noarch: W: no-manual-page-for-binary openra
openra.noarch: W: no-manual-page-for-binary openra-editor
Each executable in standard binary directories should have a man page.
```

and found some more files in mods/*/maps that had chmod +x set.