Add libzephyr4 to ubuntu-precise; resolves travis-ci/apt-package-whitelist#1901
Add libzephyr4 to ubuntu-precise; resolves travis-ci/apt-package-whitelist#1901

Packages: libzephyr4 libzephyr4-krb5 zephyr-clients zephyr-server zephyr-server-krb5 libzephyr-dev

travis-ci/apt-package-whitelist,travis-ci/apt-package-whitelist