Repackage multidex correctly
Repackage multidex correctly

Summary:we were giving up if assets/secondary-program-dex-jars wasn't there,
but that's an FB thing.  TIL.

Reviewed By: dariorussi

Differential Revision: D3186522

fb-gh-sync-id: 2c6240bed2f915e569a3f14d687e2b4393b96bd4
fbshipit-source-id: 2c6240bed2f915e569a3f14d687e2b4393b96bd4

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex