Updates the depot_tools repository URL in the docs.

Review URL: https://codereview.chromium.org/809473002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@293398 0039d316-1c4b-4281-b951-d872f2087c98

man/src/depot_tools_tutorial.txt

@@ -71,7 +71,7 @@ Clone the 'depot_tools' repository:
 
 [subs="quotes"]
 ----
-[white]**$ git clone https://chromium.googlesource.com/chromium/tools/depot_tools**
+[white]**$ git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git**
 ----
 
 Add 'depot_tools' to the 'end' of your PATH (you will probably want to put this