Address issue of python36-libvirt for kvm/SG CentOS users (#135)

* address issue of python36-libvirt for kvm/SG CentOS users

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

* Update source/releasenotes/about.rst

Co-authored-by: dahn <daan.hoogland@gmail.com>
Co-authored-by: Andrija Panic <45762285+andrijapanicsb@users.noreply.github.com>
Co-authored-by: dahn <daan.hoogland@gmail.com>
diff --git a/source/installguide/hypervisor/kvm.rst b/source/installguide/hypervisor/kvm.rst
index a498d27..bb1756a 100644
--- a/source/installguide/hypervisor/kvm.rst
+++ b/source/installguide/hypervisor/kvm.rst
@@ -153,6 +153,7 @@
 
 .. parsed-literal::
 
+   $ yum install -y epel-release
    $ yum install cloudstack-agent
 
 In Ubuntu:
diff --git a/source/installguide/hypervisor/lxc.rst b/source/installguide/hypervisor/lxc.rst
index a0b88d7..4ee9434 100644
--- a/source/installguide/hypervisor/lxc.rst
+++ b/source/installguide/hypervisor/lxc.rst
@@ -149,6 +149,7 @@
 
 .. parsed-literal::
 
+   $ yum install -y epel-release
    $ yum install cloudstack-agent
 
 In Ubuntu:
diff --git a/source/quickinstallationguide/qig.rst b/source/quickinstallationguide/qig.rst
index 38642c3..c5ee82b 100644
--- a/source/quickinstallationguide/qig.rst
+++ b/source/quickinstallationguide/qig.rst
@@ -536,6 +536,7 @@
 
 .. parsed-literal::
 
+   # yum -y install epel-release
    # yum -y install cloudstack-agent
 
 
diff --git a/source/releasenotes/about.rst b/source/releasenotes/about.rst
index c746d74..fefdb1e 100644
--- a/source/releasenotes/about.rst
+++ b/source/releasenotes/about.rst
@@ -46,6 +46,11 @@
 
 Apache CloudStack powers numerous elastic Cloud computing services, including solutions that have ranked as Gartner Magic Quadrant leaders. Highlighted in the Forrester Q4 2017 Enterprise Open Source Cloud Adoption report, Apache CloudStack "sits beneath hundreds of service provider clouds", including Fortune 5 multinational corporations. A list of known Apache CloudStack users are available at http://cloudstack.apache.org/users.html
 
+Libvirt Python Dependency on KVM and CentOS
+===========================================
+
+For CentOS users using the security groups feature on KVM it is needed to install the epel-release and python36-libvirt packages.
+
 New User Interface & Depreciation notice of existing UI
 =======================================================
 
@@ -58,4 +63,3 @@
 In the following release (likely to be 4.16), the old UI will be deprecated.
 
 Please see `Primate install guide <../installguide/primate.html>`_
-
diff --git a/source/upgrading/upgrade/upgrade-4.11.rst b/source/upgrading/upgrade/upgrade-4.11.rst
index e12f682..c3d920e 100644
--- a/source/upgrading/upgrade/upgrade-4.11.rst
+++ b/source/upgrading/upgrade/upgrade-4.11.rst
@@ -302,6 +302,8 @@
 
    .. parsed-literal::
 
+      $ sudo yum install -y epel-release
+      $ sudo yum install -y python36-libvirt
       $ sudo yum upgrade cloudstack-agent
 
 #. Restart the agent:
diff --git a/source/upgrading/upgrade/upgrade-4.13.rst b/source/upgrading/upgrade/upgrade-4.13.rst
index a85b833..753afe2 100644
--- a/source/upgrading/upgrade/upgrade-4.13.rst
+++ b/source/upgrading/upgrade/upgrade-4.13.rst
@@ -281,6 +281,8 @@
 
    .. parsed-literal::
 
+      $ sudo yum install -y epel-release
+      $ sudo yum install -y python36-libvirt
       $ sudo yum upgrade cloudstack-agent
 
 #. Restart the agent:
diff --git a/source/upgrading/upgrade/upgrade-4.9.rst b/source/upgrading/upgrade/upgrade-4.9.rst
index 13ae88f..eda121a 100644
--- a/source/upgrading/upgrade/upgrade-4.9.rst
+++ b/source/upgrading/upgrade/upgrade-4.9.rst
@@ -383,6 +383,8 @@
 
    .. parsed-literal::
 
+      $ sudo yum install -y epel-release
+      $ sudo yum install -y python36-libvirt
       $ sudo yum upgrade cloudstack-agent
 
 #. Verify that the file ``/etc/cloudstack/agent/environment.properties`` has a