Fixed path in warning

travis/install_osx.sh

@@ -47,7 +47,7 @@ clang-3.7)     install_brew_package llvm@3.7 --with-clang --with-libcxx;;
 clang-3.8)     install_brew_package llvm@3.8 --with-clang --with-libcxx;;
 clang-3.9)     install_brew_package llvm@3.9 --with-clang --with-libcxx;;
 clang-4.0)     install_brew_package llvm     --with-clang --with-libcxx;;
-*) echo "Compiler not supported: ${COMPILER}. See travis_ci_install_osx.sh"; exit 1 ;;
+*) echo "Compiler not supported: ${COMPILER}. See travis/install_osx.sh"; exit 1 ;;
 esac
 travis_fold end brew_install_util