Added Debian 7 support

Signed-off-by: Nick Chappell <nick@intronic.org>

Taken from: https://github.com/Icinga/puppet-icinga2/pull/9

refs #7264, https://dev.icinga.org/issues/7264
Fix for wrong package name in Debian 7

Signed-off-by: Nick Chappell <nick@intronic.org>

Taken from: https://github.com/Icinga/puppet-icinga2/pull/9

refs #7264, https://dev.icinga.org/issues/7264
Fix on metadata #7264

Signed-off-by: Nick Chappell <nick@intronic.org>

Taken from: https://github.com/Icinga/puppet-icinga2/pull/9

refs #7264, https://dev.icinga.org/issues/7264