Drop dep on libmysqlclient-dev

It was required to build MySQL-python bindings but, for some time,
we test and rely solely on PyMySQL which is pure Python and hence
does not require this dep.

This package is going away as distros move towards MariaDB.

Change-Id: I6004ccf28a23009a0fc07bfc9458b59a927b969a

files/debs/general

@@ -14,7 +14,6 @@ iputils-ping
 libapache2-mod-proxy-uwsgi
 libffi-dev # for pyOpenSSL
 libjpeg-dev # Pillow 3.0.0
-libmysqlclient-dev  # MySQL-python
 libpcre3-dev # for python-pcre
 libpq-dev  # psycopg2
 libssl-dev # for pyOpenSSL

files/debs/neutron-common

@@ -6,7 +6,6 @@ haproxy # to serve as metadata proxy inside router/dhcp namespaces
 iptables
 iputils-arping
 iputils-ping
-libmysqlclient-dev
 mysql-server #NOPRIME
 postgresql-server-dev-all
 python3-mysqldb

files/debs/nova

@@ -8,7 +8,6 @@ iptables
 iputils-arping
 kpartx
 libjs-jquery-tablesorter # Needed for coverage html reports
-libmysqlclient-dev
 libvirt-clients # NOPRIME
 libvirt-daemon-system # NOPRIME
 libvirt-dev # NOPRIME