Add gitweb file/root tree links to init step

These are now required in Gerrit 2.9 and above, so add them during
the plugin init phase.

Change-Id: I561bfefe253db65917730a6492eb4a4bc464e4f6

src/main/java/com/googlesource/gerrit/plugins/gitblit/GitBlitInitStep.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/gitblit/GitBlitInitStep.java b/src/main/java/com/googlesource/gerrit/plugins/gitblit/GitBlitInitStep.java
index 345a70a..8b41c4e 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/gitblit/GitBlitInitStep.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/gitblit/GitBlitInitStep.java
@@ -51,6 +51,8 @@
     gitWeb.set("revision", pluginName + "/commit/?r=${project}&h=${commit}");
     gitWeb.set("branch", pluginName + "/log/?r=${project}&h=${branch}");
     gitWeb.set("filehistory", pluginName + "/history/?f=${file}&r=${project}&h=${branch}");
+    gitWeb.set("file", pluginName + "/blob/?r=${project}&h=${commit}&f=${file}");
+    gitWeb.set("roottree", pluginName + "/tree/?r=${project}&h=${commit}");
     gitWeb.string("Link name", "linkname", "GitBlit");
   }