Merge pull request #2106 from x-way/catch-network-plugin-exceptions

Catch network exceptions (UnknownHostException etc.)

src/main/scala/gitbucket/core/plugin/PluginRepository.scala

@@ -11,9 +11,13 @@ object PluginRepository {
   }
 
   def getPlugins(): Seq[PluginMetadata] = {
+    try {
       val url = new java.net.URL("https://plugins.gitbucket-community.org/releases/plugins.json")
       val str = IOUtils.toString(url, "UTF-8")
       parsePluginJson(str)
+    } catch {
+      case _: Throwable => Nil
+    }
   }
 
 }