Summary:
This is an interim solution that unblocks failing FBOSS OSS builds.

Broadcom's OpenNSA is available on github and contains large precompiled
libraries. For large files (> 100Mb), github uses git-lfs.

git clones to OpenNSA started failing yesterday with:

Error downloading object: lib/x86-64/libopennsa.a (7f21d94): Smudge error:
Error downloading lib/x86-64/libopennsa.a
(7f21d941ac32ccae38adb05b3386be739bdccd502a878364d386e7a5cb172f35): batch
response: This repository is over its data quota. Account responsible for LFS
bandwidth should purchase more data packs to restore access.

Github documents (refer:
https://help.github.com/en/github/managing-large-files/about-storage-and-bandwidth-usage)
“When you download a file tracked with Git LFS, the total file size is counted
against the repository owner’s bandwidth limit”. It appears we are hitting that
limit.

Thus, github is not a good choice here. Even if we create a 'github release
tarball', the tarball continues to carry lfs files and thus downloading those
counts towards the quota (which is limited).

Broadcom paid some amount to bump up the quota, but it is matter of time before
we hit it esp given that these builds run on-diff.

A better solution is to download a tarball (that contains real files, not lfs),
and then allow Facebook lfs to cache it.

While github does not support that, it seems bitbucket does.

Thus, we forked OpenNSA from github into a bitbucket repo and this patch
modifies the manifest to download a tarball from bitbucket that will be cached.

Broadcom is working on a cleaner solution but this will keep our FBOSS OSS build
clean in the interim.

Reviewed By: wez

Differential Revision: D19437386

fbshipit-source-id: b1213a186a0af57b9fd71b30e8899e80affd4cc0