Adds mysql-client to POL Dockerfile

Change-Id: I5416e65239764e9475014004dbc8e698a45d8bb4
Signed-off-by: Benjamin Diaz <bdiaz@whitestack.com>
diff --git a/docker/POL/Dockerfile b/docker/POL/Dockerfile
index 148e742..fde710f 100644
--- a/docker/POL/Dockerfile
+++ b/docker/POL/Dockerfile
@@ -25,13 +25,8 @@
 LABEL authors="Benjamín Díaz"
 
 RUN apt-get --yes update \
- && apt-get --yes install python3 python3-pip libmysqlclient-dev git \
- && pip3 install pip==9.0.3
-
-RUN apt-get update && apt-get -y install curl software-properties-common
-
-RUN apt-get --yes update \
  && apt-get --yes install git python python-pip python3 python3-pip libmysqlclient-dev libssl-dev libffi-dev \
+ && apt-get --yes install mysql-client curl software-properties-common \
  && pip3 install pip==9.0.3
 
 ARG REPOSITORY_BASE=http://osm-download.etsi.org/repository/osm/debian