Bump ODL release version

ODL 6 bumped version to 6.2.
Without setting version, karaf is not able to install some
required features.

http://cbs.centos.org/repos/nfv7-opendaylight-6-release/x86_64/os/Packages/

Change-Id: I12101accff2f76dee9b145d2d6dcab7d8a15719b
Closes-Bug: #1740043