Use https for repo, mention md5sum

Change-Id: I67c2e2f14157a353e285cdf365ed5a228ab5d38e
diff --git a/src/source/downloading.md b/src/source/downloading.md
index d932efa..7a120b8 100644
--- a/src/source/downloading.md
+++ b/src/source/downloading.md
@@ -29,9 +29,10 @@
 
  - Download the Repo script and ensure it is executable:
 
-        $ curl http://android.git.kernel.org/repo > ~/bin/repo
+        $ curl https://android.git.kernel.org/repo > ~/bin/repo
         $ chmod a+x ~/bin/repo
 
+ - The MD5 checksum for repo is bbf05a064c4d184550d71595a662e098
 
 ## Initializing a Repo client ##