Add missing packages to charm hook.

Fixes 'ImportError: No module named MySQLdb' error in apache2/error.log
by installing libmysqlclient-dev and mysql-python.

charms/garr-dashboard/hooks/hooks.py

@@ -19,6 +19,11 @@ from charmhelpers.core.hookenv import (
     WARNING
 )
 
+from charmhelpers.fetch import (
+    apt_install,
+    apt_purge,
+    apt_update,
+)
 
 def dashboard_plugin_context():
     for rid in relation_ids("dashboard-plugin"):
@@ -147,6 +152,8 @@ def dashboard_plugin_relation_changed():
     install_project_costs_plugin(ctxt['openstack_dir'])
     install_admin_costs_plugin(ctxt['openstack_dir'])
     install_theme(ctxt['openstack_dir'])
+    apt_install('libmysqlclient-dev', fatal=True)
+    pip_install('mysql-python', fatal=True)
     pip_install('gnocchiclient==3.3.1', fatal=True)
     pip_install('sqlalchemy==1.2.0', fatal=True)
     service_restart('apache2')