Use sensible defaults in the dev server

When no config file is present, default to exporting all git
repositories under the current directory and making templates
reloadable. Move some of the default dev-specific behavior out of
GitilesFilter and into DevServer, including removing the
gitiles.reloadTemplates config option entirely.

Change-Id: Ibf62d49ed2a77ff232d5477b326c3f03e98895fb

gitiles-servlet/src/main/java/com/google/gitiles/DefaultUrls.java

diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/DefaultUrls.java b/gitiles-servlet/src/main/java/com/google/gitiles/DefaultUrls.java
index 6495b5d..83c5436 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/DefaultUrls.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/DefaultUrls.java
@@ -40,7 +40,7 @@
       this.canonicalHostName = InetAddress.getLocalHost().getCanonicalHostName();
     }
     this.baseGitUrl = checkNotNull(baseGitUrl, "baseGitUrl");
-    this.baseGerritUrl = checkNotNull(baseGerritUrl, "baseGerritUrl");
+    this.baseGerritUrl = baseGerritUrl;
   }
 
   @Override