Upgrade to Gerrit version 2.15.3

Change-Id: I1bb588ce34c2fcacc00aa4cd6155638722eafc9f
diff --git a/centos/7/Dockerfile b/centos/7/Dockerfile
index 93c998d..08dde08 100644
--- a/centos/7/Dockerfile
+++ b/centos/7/Dockerfile
@@ -10,7 +10,7 @@
 # Install OpenJDK and Gerrit in two subsequent transactions
 # (pre-trans Gerrit script needs to have access to the Java command)
 RUN yum -y install java-1.8.0-openjdk
-RUN yum -y install gerrit-2.15.2-1  && rm -f /var/gerrit/logs/*
+RUN yum -y install gerrit-2.15.3-1  && rm -f /var/gerrit/logs/*
 
 USER gerrit
 RUN java -jar /var/gerrit/bin/gerrit.war init --batch --install-all-plugins -d /var/gerrit
diff --git a/ubuntu/16/Dockerfile b/ubuntu/16/Dockerfile
index 09a9f63..88ace7f 100644
--- a/ubuntu/16/Dockerfile
+++ b/ubuntu/16/Dockerfile
@@ -13,7 +13,7 @@
 # Install OpenJDK and Gerrit in two subsequent transactions
 # (pre-trans Gerrit script needs to have access to the Java command)
 RUN apt-get -y install openjdk-8-jdk
-RUN apt-get -y install gerrit=2.15.2-1 && rm -f /var/gerrit/logs/*
+RUN apt-get -y install gerrit=2.15.3-1 && rm -f /var/gerrit/logs/*
 
 USER gerrit
 RUN java -jar /var/gerrit/bin/gerrit.war init --batch --install-all-plugins -d /var/gerrit