Add mysql devel as testonly alongside mysql-server

Neutron needs to be able to install MySQL-python in the functional
test job, which requires devstack to install mysql devel libraries as
testonly.

As per sdague's recommendation mysql devel libraries are now installed
for nova as well.  In the future, any service that installs
mysql-server should also install mysql devel libraries for consistency.

Related-bug: #1346444

Change-Id: Ie715841e33a2c2d31cb4ac724b302eb98ed3366a

files/apts/neutron

@@ -2,6 +2,7 @@ ebtables
 iptables
 iputils-ping
 iputils-arping
+libmysqlclient-dev  # testonly
 mysql-server #NOPRIME
 sudo
 python-boto

files/apts/nova

@@ -4,6 +4,7 @@ conntrack
 kpartx
 parted
 iputils-arping
+libmysqlclient-dev  # testonly
 mysql-server # NOPRIME
 python-mysqldb
 python-mysql.connector

files/rpms/neutron

@@ -5,6 +5,7 @@ ebtables
 iptables
 iputils
 mysql-connector-python
+mysql-devel  # testonly
 mysql-server # NOPRIME
 openvswitch # NOPRIME
 python-boto

files/rpms/nova

@@ -16,6 +16,7 @@ libxml2-python
 numpy # needed by websockify for spice console
 m2crypto
 mysql-connector-python
+mysql-devel  # testonly
 mysql-server # NOPRIME
 parted
 polkit