pom: Fix plugin name to be all lowercase

Tests fail if you use the maven built jar otherwise.

Change-Id: I5cc3da7f55abd399a33b18a432aad4a7664c55b7
diff --git a/pom.xml b/pom.xml
index fecdcb7..dfd207a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -39,7 +39,7 @@
         <configuration>
           <archive>
             <manifestEntries>
-              <Gerrit-PluginName>Batch</Gerrit-PluginName>
+              <Gerrit-PluginName>batch</Gerrit-PluginName>
               <Gerrit-Module>com.googlesource.gerrit.plugins.batch.Module</Gerrit-Module>
               <Gerrit-SshModule>com.googlesource.gerrit.plugins.batch.ssh.SshModule</Gerrit-SshModule>