In the release of Ubuntu 14.04 it would now appear that the likewise open package has been removed from the repository and there is no source package available.
However, as mentioned at the following article http://www.tecmint.com/integrate-ubuntu-14-04-to-zentyal-pdc/ you can manually download and install the packages. I only followed the steps to download and install the likewise-open and libglade packages as I do not require the GUI package.
To manually download and install the required packages as above, invoke the following:
$ wget http://de.archive.ubuntu.com/ubuntu/pool/main/l/likewise-open/likewise-open_6.1.0.406-0ubuntu10_amd64.deb $ wget http://de.archive.ubuntu.com/ubuntu/pool/main/libg/libglade2/libglade2-0_2.6.4-1ubuntu3_amd64.deb $ sudo dpkg -i likewise-open_6.1.0.406-0ubuntu10_amd64.deb $ sudo dpkg -i libglade2-0_2.6.4-1ubuntu3_amd64.deb
However, I received the following error, when attempting to install the libglade2-0:amd64 package:
dpkg: error processing package libglade2-0:amd64 (--install): dependency problems - leaving unconfigured Errors were encountered while processing:libglade2-0:amd64
All I was required to do was to run ‘sudo apt-get -f install‘ to install any dependencies the libglade package required and following this I was able to invoke ‘domainjoin-cli‘ from the installed likewise open package.