ccnl: fixed commenting style
ccnl: eliminated empty translation unit warning
make: rename VERSION into RIOT_VERSION

Building MSP boards gives an error, because `VERSION` is somewhere
defined in their toolchain as an integer.

This PR renames `VERSION` into `RIOT_VERSION`, because that's what it
is.
Merge pull request #1400 from Kijewski/riot-version

make: rename VERSION into RIOT_VERSION
Merge pull request #1362 from OlegHahm/ccnl_eliminate_warning

CCN_lite eliminate warning