Change CentOS in documentation

Change-Id: Ic4725a4cef02a57e837c727378a99bf7575d4ebd

doc/image-building.rst

@@ -13,7 +13,7 @@ In general, you will build images like this:
 
     $ tools/build.py
 
-By default, the above command would build all images based on centos image.
+By default, the above command would build all images based on CentOS image.
 
 If you want to change the base distro image, add ``-b``:
 

doc/quickstart.rst

@@ -70,7 +70,7 @@ Make sure the "pip" package manager is installed before proceeding:
 
 ::
 
-    # Centos 7
+    # CentOS 7
     yum install epel-release
     yum install python-pip
 
@@ -145,7 +145,7 @@ following requirements are needed to build the client code:
    # Ubuntu
    apt-get install -y python-dev libffi-dev libssl-dev gcc git
 
-   # Centos 7
+   # CentOS 7
    yum install -y python-devel libffi-devel openssl-devel gcc git
 
 To install these clients use:
@@ -199,7 +199,7 @@ To install, start, and enable ntp on CentOS execute the following:
 
 ::
 
-    # Centos 7
+    # CentOS 7
     yum -y install ntp
     systemctl enable ntpd.service
     systemctl start ntpd.service
@@ -216,7 +216,7 @@ be running at a time.
 
 ::
 
-    # Centos 7
+    # CentOS 7
     systemctl stop libvirtd.service
     systemctl disable libvirtd.service
 
@@ -249,7 +249,7 @@ system. Install it using system packaging tools if it's not installed already:
 
 ::
 
-    # Centos 7
+    # CentOS 7
     yum -y install gcc
 
     # Ubuntu
@@ -322,7 +322,7 @@ And restart docker by executing the following commands:
 
 ::
 
-    # Centos
+    # CentOS
     systemctl daemon-reload
     systemctl stop docker
     systemctl start docker
@@ -345,7 +345,7 @@ or the build process will fail. To build images using default parameters run:
 
     kolla-build
 
-By default kolla-build will build all containers using Centos as the base
+By default kolla-build will build all containers using CentOS as the base
 image and binary installation as base installation method. To change this
 behavior, please use the following parameters with kolla-build:
 

doc/vagrant-dev-env.rst

@@ -76,7 +76,7 @@ Find a location in the system's home directory and checkout the Kolla repo::
     git clone https://github.com/openstack/kolla.git
 
 Developers can now tweak the Vagrantfile or bring up the default AIO
-Centos7-based environment::
+CentOS 7-based environment::
 
     cd kolla/dev/vagrant && vagrant up