Add shntool to ubuntu-precise; resolves travis-ci/apt-package-whitelist#754
Add shntool to ubuntu-precise; resolves travis-ci/apt-package-whitelist#754

Packages: shntool

AlCutter/apt-package-whitelist,jschlyter/apt-package-whitelist,jschlyter/apt-package-whitelist,christophgysin/apt-package-whitelist,phw/apt-package-whitelist,AlCutter/apt-package-whitelist,jmerkow/apt-package-whitelist,jmerkow/apt-package-whitelist,sternb0t/apt-package-whitelist,Tyrael/apt-package-whitelist,Tyrael/apt-package-whitelist,travis-ci/apt-package-whitelist,travis-ci/apt-package-whitelist,sternb0t/apt-package-whitelist,christophgysin/apt-package-whitelist,phw/apt-package-whitelist