Merge pull request #256 from konstruktoid/date_255

busybox date conversion

Author: konstruktoid

tests/1_host_configuration.sh

@@ -22,7 +22,7 @@ note "$check_1_2"
 check_1_3="1.3  - Ensure Docker is up to date"
 docker_version=$(docker version | grep -i -A1 '^server' | grep -i 'version:' \
   | awk '{print $NF; exit}' | tr -d '[:alpha:]-,')
-docker_current_version="$(date --date="$(date +%y-%m-1) -1 month" +%y.%m.0)"
+docker_current_version="$(date +%y.%m.0 -d @$(( $(date +%s) - 2592000)))"
 do_version_check "$docker_current_version" "$docker_version"
 if [ $? -eq 11 ]; then
   info "$check_1_3"