[doc]: Fix glance image_metadata link

Change-Id: Ib1e3798992696cf5f271b20bc731b8b766d173ac
Closes-Bug: #1900731
(cherry picked from commit f5a6882)

Author: Balazs Gibizer

doc/source/admin/configuration/hypervisor-xen-libvirt.rst

@@ -158,7 +158,7 @@ Use the following as a guideline for configuring Xen for use in OpenStack:
       $ openstack image set --property hypervisor_type=xen vm_mode=hvm IMAGE
 
    For more information on image metadata, refer to the `OpenStack Virtual
-   Image Guide <https://docs.openstack.org/image-guide/image-metadata.html>`__.
+   Image Guide <https://docs.openstack.org/image-guide/introduction.html#image-metadata>`__.
 
 #. **Libguestfs file injection**: OpenStack compute nodes can use `libguestfs
    <http://libguestfs.org/>`_ to inject files into an instance's image prior to

doc/source/admin/cpu-topologies.rst

@@ -665,6 +665,6 @@ memory allocation turned on. The Hyper-V driver will ignore the configured
 instances with a NUMA topology.
 
 .. Links
-.. _`Image metadata`: https://docs.openstack.org/image-guide/image-metadata.html
+.. _`Image metadata`: https://docs.openstack.org/image-guide/introduction.html#image-metadata
 .. _`discussion`: http://lists.openstack.org/pipermail/openstack-dev/2016-March/090367.html
 .. _`MTTCG project`: http://wiki.qemu.org/Features/tcg-multithread

doc/source/admin/huge-pages.rst

@@ -239,4 +239,4 @@ guide.
 .. Links
 .. _`Linux THP guide`: https://www.kernel.org/doc/Documentation/vm/transhuge.txt
 .. _`Linux hugetlbfs guide`: https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt
-.. _`Image metadata`: https://docs.openstack.org/image-guide/image-metadata.html
+.. _`Image metadata`: https://docs.openstack.org/image-guide/introduction.html#image-metadata