Update usage comment.


git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@133020 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/git-svn/convert.py b/utils/git-svn/convert.py
index efd09ae..c230a01 100755
--- a/utils/git-svn/convert.py
+++ b/utils/git-svn/convert.py
@@ -7,8 +7,8 @@
 
 1. Mail.app -> Save As -> api.eml (Raw Message Source)
 2. .../convert.py api.eml
-3. git am --signoff < api.eml
-4. git svn dcommit
+3. git am [--signoff] < api.eml
+4. git svn dcommit [--commit-url https://id@llvm.org/svn/llvm-project/lldb/trunk]
 """
 
 import os, re, sys