Avoid double slash in REST calls made from the GerritRestApi

Change-Id: I2742411bc801e113e487bf5c9cbb26ede35d2bd5
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/GerritRestApi.java b/src/main/java/com/googlesource/gerrit/plugins/replication/GerritRestApi.java
index 91fe20a..55fbed1 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/GerritRestApi.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/GerritRestApi.java
@@ -125,8 +125,8 @@
       u = u.substring(GERRIT_ADMIN_PROTOCOL_PREFIX.length());
     }
     if (u.endsWith("/")) {
-      return u;
+      return u.substring(0, u.length() - 1);
     }
-    return u + "/";
+    return u;
   }
 }