doc: Use dnf instead of yum

The yum command has been replaced by the dnf command in recent releases
of Fedora-based distributions. Use the native command instead of
the alias kept for compatibility.

Change-Id: I0a1dfdaca91164eff2c25795f66976ec70356574
diff --git a/doc/source/guides/multinode-lab.rst b/doc/source/guides/multinode-lab.rst
index 658422b..4b50b2c 100644
--- a/doc/source/guides/multinode-lab.rst
+++ b/doc/source/guides/multinode-lab.rst
@@ -24,7 +24,7 @@
 
 ::
 
-    apt-get install -y git sudo || yum install -y git sudo
+    apt-get install -y git sudo || dnf install -y git sudo
 
 Network Configuration
 ---------------------
diff --git a/doc/source/guides/single-machine.rst b/doc/source/guides/single-machine.rst
index a4385b5..263fbb9 100644
--- a/doc/source/guides/single-machine.rst
+++ b/doc/source/guides/single-machine.rst
@@ -62,7 +62,7 @@
 
 .. code-block:: console
 
-    $ apt-get install sudo -y || yum install -y sudo
+    $ apt-get install sudo -y || dnf install -y sudo
     $ echo "stack ALL=(ALL) NOPASSWD: ALL" | sudo tee /etc/sudoers.d/stack
 
 .. note:: On some systems you may need to use ``sudo visudo``.
@@ -81,7 +81,7 @@
 
 .. code-block:: console
 
-    $ sudo apt-get install git -y || sudo yum install -y git
+    $ sudo apt-get install git -y || sudo dnf install -y git
     $ git clone https://opendev.org/openstack/devstack
     $ cd devstack
 
diff --git a/doc/source/guides/single-vm.rst b/doc/source/guides/single-vm.rst
index 7dac18b..4272a4b 100644
--- a/doc/source/guides/single-vm.rst
+++ b/doc/source/guides/single-vm.rst
@@ -56,8 +56,8 @@
     write_files:
       - content: |
             #!/bin/sh
-            DEBIAN_FRONTEND=noninteractive sudo apt-get -qqy update || sudo yum update -qy
-            DEBIAN_FRONTEND=noninteractive sudo apt-get install -qqy git || sudo yum install -qy git
+            DEBIAN_FRONTEND=noninteractive sudo apt-get -qqy update || sudo dnf update -qy
+            DEBIAN_FRONTEND=noninteractive sudo apt-get install -qqy git || sudo dnf install -qy git
             sudo chown stack:stack /home/stack
             cd /home/stack
             git clone https://opendev.org/openstack/devstack
diff --git a/doc/source/networking.rst b/doc/source/networking.rst
index 05b4f34..10e1c3f 100644
--- a/doc/source/networking.rst
+++ b/doc/source/networking.rst
@@ -213,7 +213,7 @@
 
 .. code-block:: bash
 
-    sudo apt-get install sshuttle || yum install sshuttle
+    sudo apt-get install sshuttle || dnf install sshuttle
 
 Finally, start ``sshuttle`` on your localhost using the floating IP address
 range. For example, assuming you are using the default value for
diff --git a/doc/source/plugins.rst b/doc/source/plugins.rst
index dd75b5a..fe567e2 100644
--- a/doc/source/plugins.rst
+++ b/doc/source/plugins.rst
@@ -232,7 +232,7 @@
 plugin as files that contain new-line separated lists of packages
 required by the plugin
 
-Supported packaging systems include apt and yum across multiple
+Supported packaging systems include apt and dnf across multiple
 distributions.  To enable a plugin to hook into this and install
 package dependencies, packages may be listed at the following
 locations in the top-level of the plugin repository: