[install] Cleanup Distro section

Remove ".. end", those are not needed anymore.
Sort entries of releases so that latest release is first for RDO (as
done with Ubuntu and OBS already).

Change-Id: Iff837d56c9a2770622f7a5caf3dd7a31a99acb5e

doc/install-guide/source/environment-packages-rdo.rst

@@ -51,8 +51,6 @@ Prerequisites
       # subscription-manager repos --enable=rhel-7-server-optional-rpms \
         --enable=rhel-7-server-extras-rpms --enable=rhel-7-server-rh-common-rpms
 
-   .. end
-
 Enable the OpenStack repository
 -------------------------------
 
@@ -61,13 +59,11 @@ Enable the OpenStack repository
   default, so you can simply install the package to enable the OpenStack
   repository.
 
-  **When installing the Pike release, run:**
+  **When installing the Rocky release, run:**
 
   .. code-block:: console
 
-     # yum install centos-release-openstack-pike
-
-  .. end
+       # yum install centos-release-openstack-rocky
 
   **When installing the Queens release, run:**
 
@@ -75,15 +71,11 @@ Enable the OpenStack repository
 
      # yum install centos-release-openstack-queens
 
-  .. end
-
-  **When installing the Rocky release, run:**
+  **When installing the Pike release, run:**
 
   .. code-block:: console
 
-       # yum install centos-release-openstack-rocky
-
-  .. end
+     # yum install centos-release-openstack-pike
 
 * On RHEL, download and install the RDO repository RPM to enable the
   OpenStack repository.
@@ -92,8 +84,6 @@ Enable the OpenStack repository
 
      # yum install https://rdoproject.org/repos/rdo-release.rpm
 
-  .. end
-
   The RDO repository RPM installs the latest available OpenStack release.
 
 Finalize the installation
@@ -105,8 +95,6 @@ Finalize the installation
 
       # yum upgrade
 
-   .. end
-
    .. note::
 
       If the upgrade process includes a new kernel, reboot your host
@@ -118,8 +106,6 @@ Finalize the installation
 
       # yum install python-openstackclient
 
-   .. end
-
 3. RHEL and CentOS enable :term:`SELinux` by default. Install the
    ``openstack-selinux`` package to automatically manage security
    policies for OpenStack services:
@@ -127,5 +113,3 @@ Finalize the installation
    .. code-block:: console
 
       # yum install openstack-selinux
-
-   .. end

doc/install-guide/source/environment-packages-ubuntu.rst

@@ -30,8 +30,6 @@ Enable the OpenStack repository
    # apt install software-properties-common
    # add-apt-repository cloud-archive:queens
 
-.. end
-
 **OpenStack Pike:**
 
 .. code-block:: console
@@ -39,8 +37,6 @@ Enable the OpenStack repository
    # apt install software-properties-common
    # add-apt-repository cloud-archive:pike
 
-.. end
-
 .. note::
 
    The Ubuntu Cloud Archive pockets for Pike and Queens provide
@@ -58,8 +54,6 @@ Finalize the installation
 
       # apt update && apt dist-upgrade
 
-   .. end
-
    .. note::
 
       If the upgrade process includes a new kernel, reboot your host
@@ -70,5 +64,3 @@ Finalize the installation
    .. code-block:: console
 
       # apt install python-openstackclient
-
-   .. end