Add sha-1 for repo launcher 1.20

This also updates the url to download repo.

Change-Id: I4d3f9c41c44b5b995ff983af035d2cd48d072073
diff --git a/src/source/downloading.jd b/src/source/downloading.jd
index 6d4212e..e4dd24b 100644
--- a/src/source/downloading.jd
+++ b/src/source/downloading.jd
@@ -55,7 +55,7 @@
       Download the Repo tool and ensure that it is executable:
     </p>
     <pre>
-$ curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo &gt; ~/bin/repo
+$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo &gt; ~/bin/repo
 $ chmod a+x ~/bin/repo
 </pre>
   </li>
@@ -66,6 +66,9 @@
 <p>
   For version 1.19, the SHA-1 checksum for repo is 92cbad8c880f697b58ed83e348d06619f8098e6c
 </p>
+<p>
+  For version 1.20, the SHA-1 checksum for repo is e197cb48ff4ddda4d11f23940d316e323b29671c
+</p>
 <h2 id="initializing-a-repo-client">
   Initializing a Repo client
 </h2>
@@ -279,4 +282,4 @@
 <p>
   If you haven't <a href="initializing.html#ccache">set up ccache</a> yet, now would be a good
   time to do it.
-</p>
\ No newline at end of file
+</p>