Switch from MySQL-python to PyMySQL

As discussed in the Liberty Design Summit "Moving apps to Python 3"
cross-project workshop, the way forward in the near future is to
switch to the pure-python PyMySQL library as a default.

https://etherpad.openstack.org/p/liberty-cross-project-python3

Change-Id: I1b66bd149aba75e565acd0d23e15a1b489ee710d

doc/source/draft/admin-guide/prepare_lab.rst

@@ -49,21 +49,17 @@ Supported Operation Systems
 
 * libffi-dev
 
-* libmysqlclient-dev
-
 * libpq-dev
 
 * python-openssl
 
 * mysql-client
 
-* python-mysqldb
-
 Install all the requirements on Ubuntu by running::
 
   # apt-get install gcc python-pip python-dev \
-  libxml2-dev libxslt-dev libffi-dev libmysqlclient-dev \
-  libpq-dev python-openssl mysql-client python-mysqldb
+  libxml2-dev libxslt-dev libffi-dev \
+  libpq-dev python-openssl mysql-client
 
 *CentOS*
 
@@ -85,13 +81,11 @@ Install all the requirements on Ubuntu by running::
 
 * mysql
 
-* MySQL-python
-
 Install all the requirements on CentOS by running::
 
   # yum install gcc python-pip python-devel libxml2-devel \
   libxslt-devel libffi-devel postgresql-devel pyOpenSSL \
-  mysql MySQL-python
+  mysql
 
 .. _lab_requirements:
 

doc/source/install/prepare.rst

@@ -44,16 +44,12 @@ System prerequisites
 
 * libffi-dev
 
-* libmysqlclient-dev
-
 * libpq-dev
 
 * python-openssl
 
 * mysql-client
 
-* python-mysqldb
-
 *CentOS*
 
 * gcc
@@ -74,8 +70,6 @@ System prerequisites
 
 * mysql
 
-* MySQL-python
-
 
 Lab Requirements
 ================

test-requirements.txt

@@ -20,7 +20,7 @@ unittest2
 pylint==1.4.1  # GNU GPL v2
 
 # Some of the tests use real MySQL and Postgres databases
-MySQL-python
+PyMySQL>=0.6.2  # MIT License
 psycopg2
 
 # doc build requirements