Add support for redis to Zaqar's lib

A new redis driver has landed in Zaqar. This patch adds support for that
driver to Zaqar's lib.

Change-Id: I97629a303c55ee098e3bfbc534bfb05ccab94649
diff --git a/lib/zaqar b/lib/zaqar
index fe25e1f..b8570eb 100644
--- a/lib/zaqar
+++ b/lib/zaqar
@@ -125,11 +125,27 @@
         iniset $ZAQAR_CONF  drivers storage mongodb
         iniset $ZAQAR_CONF 'drivers:storage:mongodb' uri mongodb://localhost:27017/zaqar
         configure_mongodb
+    elif [ "$ZAQAR_BACKEND" = 'redis' ] ; then
+        iniset $ZAQAR_CONF  drivers storage redis
+        iniset $ZAQAR_CONF 'drivers:storage:redis' uri redis://localhost:6379
+        configure_redis
     fi
 
     cleanup_zaqar
 }
 
+function configure_redis {
+    if is_ubuntu; then
+        install_package redis-server
+    elif is_fedora; then
+        install_package redis
+    else
+        exit_distro_not_supported "redis installation"
+    fi
+
+    install_package python-redis
+}
+
 function configure_mongodb {
     # Set nssize to 2GB. This increases the number of namespaces supported
     # # per database.