Set Gerrit to 2.15.21

Change-Id: I22f445d43a7aa53de4e5fce309828622c36ee648
diff --git a/docker/centos7/Makefile b/docker/centos7/Makefile
index 45c3064..8268dab 100644
--- a/docker/centos7/Makefile
+++ b/docker/centos7/Makefile
@@ -1,7 +1,7 @@
 # Customise the following variable as Make parameters
 # to produce a yum.repo for a VENDOR distribution
 # Default values are pointing to GerritForge (www.gerritforge.com)
-VERSION=2.15.20
+VERSION=2.15.21
 RELEASE=1
 REPO_VERSION=1
 REPO_RELEASE=2
diff --git a/docker/ubuntu16.04/Makefile b/docker/ubuntu16.04/Makefile
index 13dcf52..0b70075 100644
--- a/docker/ubuntu16.04/Makefile
+++ b/docker/ubuntu16.04/Makefile
@@ -1,7 +1,7 @@
 # Customise the following variable as Make parameters
 # to produce a yum.repo for a VENDOR distribution
 # Default values are pointing to GerritForge (www.gerritforge.com)
-VERSION=2.15.20
+VERSION=2.15.21
 RELEASE=1
 VENDOR=GerritForge
 VENDOR_LC=$(shell echo $(VENDOR) | tr A-Z a-z)
diff --git a/fpm/Makefile b/fpm/Makefile
index 09f1ad7..c023e00 100644
--- a/fpm/Makefile
+++ b/fpm/Makefile
@@ -1,4 +1,4 @@
-VERSION=2.15.20
+VERSION=2.15.21
 URL=https://gerrit-releases.storage.googleapis.com/gerrit-$(VERSION).war
 CI_URL=https://archive-ci.gerritforge.com
 RELEASE=1
diff --git a/macOS/Makefile b/macOS/Makefile
index 14e540a..fa37534 100644
--- a/macOS/Makefile
+++ b/macOS/Makefile
@@ -1,4 +1,4 @@
-VERSION := 2.15.20
+VERSION := 2.15.21
 
 all: server