Removed assumption on Gitblit plugin name

Now the Gerrit plugin name is on the MANIFEST.MF: we do not need anymore
then to name it as 'gitblit.jar'.

Change-Id: I18c3b964760638ffa251b0b34e8641b12de8296c
diff --git a/README.md b/README.md
index 6c6bec3..08d468b 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,6 @@
 -------------
 In order to use GitBlit as GitWeb replacement, please apply
 the following configuration to your Gerrit config.
-(assuming plugin was copied as gitblit.jar)
 
     [gitweb]
         type = custom