Update git submodules

* Update plugins/download-commands from branch 'master'
  to 6b6c50e4f487b0f1ebf316e0625669260b226879
  - repo: include patchset number in commands
    
    Since we don't include the ps number, repo will look up the latest
    one and use that.  If the user is viewing an older ps, that means
    the repo command won't actually download the version they have
    selected which can be quite confusing.
    
    The git version already includes the fully change id + ps num, so
    this brings repo up to parity.
    
    Change-Id: I6a4cd56cf9960d626770f98837028119aeaed4d4
    
diff --git a/plugins/download-commands b/plugins/download-commands
index fd650ca..6b6c50e 160000
--- a/plugins/download-commands
+++ b/plugins/download-commands
@@ -1 +1 @@
-Subproject commit fd650ca386c382b42d30e7ad72279bfeb311aee4
+Subproject commit 6b6c50e4f487b0f1ebf316e0625669260b226879