Deprecate Debian Jessie

Closes #684

Vagrantfile

@@ -51,10 +51,6 @@ Vagrant.configure("2") do |config|
     os.vm.box = "bento/ubuntu-14.04"
     provision_libretime(os, "debian.sh", installer_args)
   end
-  config.vm.define "debian-jessie" do |os|
-    os.vm.box = "bento/debian-8.7"
-    provision_libretime(os, "debian.sh", installer_args)
-  end
   config.vm.define "debian-stretch" do |os|
     os.vm.box = "bento/debian-9.6"
     provision_libretime(os, "debian.sh", installer_args)

docs/vagrant.md

@@ -97,7 +97,6 @@ offers the option to choose a different operation system according to you needs.
 | ------ | ------------------- | ------- |
 | Debian 10   | `vagrant up debian-buster`  | Install on Debian Buster. |
 | Debian 9.6   | `vagrant up debian-stretch` | Install on current Debian Stretch. |
-| Debian 8.7   | `vagrant up debian-jessie`  | Install on Debian Jessie. |
 | Ubuntu 18.04 | `vagrant up ubuntu-bionic`  | Experimental install on current Ubuntu Bionic Beaver. |
 | Ubuntu 16.04 | `vagrant up ubuntu-xenial`  | Install on Ubuntu Xenial Xerus. |
 | Ubuntu 14.04 | `vagrant up ubuntu-trusty`  | Deprecated install on Ubuntu Trusty Tahir. Recommended by legacy upstream. |

install

@@ -642,9 +642,8 @@ case "${dist}-${code}" in
         code="jessie"
         is_debian_dist=true
         echo -e "ERROR: Debian Jessie is archived and does not receive any security or other updates since 2018-05-17." >&2
-        echo -e "The LibreTime installer will drop support for installing LibreTime on Jessie in 3.0.0-alpha.8." >&2
-        sleep 6
-        is_debian_jessie=true
+        echo -e "The LibreTime installer dropped support for installing LibreTime on Jessie in 3.0.0-alpha.8." >&2
+        exit 1
         ;;
     debian-7|debian-wheezy)
         echo -e "ERROR: Debian Wheezy is archived and does not receive any security or other updates since 2018-05-31." >&2