Set Gerrit to 2.14.20

Change-Id: I5adf94b26895bcc42b5e43f689bc54d67cb62342

centos/7/Dockerfile

diff --git a/centos/7/Dockerfile b/centos/7/Dockerfile
index 1bc6451..23a3885 100644
--- a/centos/7/Dockerfile
+++ b/centos/7/Dockerfile
@@ -9,7 +9,7 @@
 # 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-2.14.19
+RUN yum -y install gerrit-2.14.20
 
 USER gerrit
 RUN java -jar /var/gerrit/bin/gerrit.war init --batch --install-all-plugins -d /var/gerrit

ubuntu/16/Dockerfile

diff --git a/ubuntu/16/Dockerfile b/ubuntu/16/Dockerfile
index 9d19571..97f5b51 100644
--- a/ubuntu/16/Dockerfile
+++ b/ubuntu/16/Dockerfile
@@ -12,7 +12,7 @@
 # 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=2.14.19-1 && rm -f /var/gerrit/logs/*
+RUN apt-get -y install gerrit=2.14.20-1 && rm -f /var/gerrit/logs/*
 
 USER gerrit
 RUN java -jar /var/gerrit/bin/gerrit.war init --batch --install-all-plugins -d /var/gerrit