Bump to Gerrit v2.15-rc4

Change-Id: Ibc898caed00453419affe4594eeb56e284a611b4
diff --git a/github-oauth/pom.xml b/github-oauth/pom.xml
index f56068a..301bfa3 100644
--- a/github-oauth/pom.xml
+++ b/github-oauth/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>com.googlesource.gerrit.plugins.github</groupId>
     <artifactId>github-parent</artifactId>
-    <version>2.15-rc3</version>
+    <version>2.15-rc4</version>
   </parent>
   <artifactId>github-oauth</artifactId>
   <name>Gerrit Code Review - GitHub OAuth login</name>
diff --git a/github-plugin/pom.xml b/github-plugin/pom.xml
index 21c5b61..948dbf7 100644
--- a/github-plugin/pom.xml
+++ b/github-plugin/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <artifactId>github-parent</artifactId>
     <groupId>com.googlesource.gerrit.plugins.github</groupId>
-    <version>2.15-rc3</version>
+    <version>2.15-rc4</version>
   </parent>
 
   <artifactId>github-plugin</artifactId>
diff --git a/pom.xml b/pom.xml
index 3ce9c3d..e5a6eba 100644
--- a/pom.xml
+++ b/pom.xml
@@ -18,7 +18,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.googlesource.gerrit.plugins.github</groupId>
   <artifactId>github-parent</artifactId>
-  <version>2.15-rc3</version>
+  <version>2.15-rc4</version>
   <name>Gerrit Code Review - GitHub integration</name>
   <url>http://www.gerritforge.com</url>
   <packaging>pom</packaging>