FIX: Prevent XMLMetadataSupplier from being copied

The class XMLMetadataSupplier belongs to a public hierarchy,
it should not be possible to copy it.
24 jobs for !707 with 2024-metadata-refac in 94 minutes and 26 seconds (queued for 4 seconds)
detached
Status Job ID Name Coverage
  Precheck
passed #28051
fast-build

00:20:57

passed #28052
legal-check

00:03:32

 
  Prepare
passed #28054
centos-xdk-prepare

00:03:29

passed #28055
macos
macos-xdk-prepare

00:00:45

passed #28053
ubuntu-xdk-prepare

00:00:34

passed #28056
windows10
windows-10-prepare

00:01:50

passed #28057
windows8
windows-8-prepare

00:01:44

 
  Build
passed #28060
centos-xdk-build

00:32:19

passed #28058
debian-build

00:40:48

passed #28061
macos
macos-xdk-build

00:13:04

passed #28059
ubuntu-xdk-build-doc

00:42:07

passed #28064
ubuntu-xdk-qa-code-coverage

01:06:00

passed #28065
ubuntu-xdk-qa-static-analysis

01:08:10

passed #28062
windows10
windows-10-build

01:05:54

passed #28063
windows8
windows-8-build

00:58:48

 
  Report
passed #28066
ubuntu-xdk-report

00:04:41

 
  External
passed cdash:centos-6.6-gcc

passed cdash:debian-testing-gcc

passed cdash:macos-10.11.6-clang

passed cdash:ubuntu-18.04-fast

passed cdash:ubuntu-18.04-llvm-qa

passed cdash:ubuntu-18.04-llvm-xdk

passed cdash:windows-10-x64-vc14.0

passed cdash:windows-8.1-x86-vc14.0