Update shipping version of vs_addin.

This brings in the following changes to the addin:
r1578 Add default compiler include paths to visual studio
r1577 Cleanup create_package.py
r1576 Fix several issues with debugging PPAPI plugins
r1575 Update versions used for testing the addin
r1574 Only skip uploading of addin if the file already exists on google storage.

BUG= https://code.google.com/p/chromium/issues/detail?id=179121
R=binji@chromium.org

Review URL: https://codereview.chromium.org/604083003

Cr-Commit-Position: refs/heads/master@{#296813}

native_client_sdk/src/build_tools/json/naclsdk_manifest2.json

@@ -29,7 +29,7 @@
       "name": "vs_addin",
       "recommended": "no",
       "repath": "vs_addin",
-      "revision": 1573,
+      "revision": 1578,
       "stability": "dev",
       "version": 0
     },