Add error exit status when commit fails [skip ci]
Add error exit status when commit fails [skip ci]

So that the checker can alert and construct a meaningful message

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