xccl/core: Bug fix in the OOB allgather code

[pavanbalaji]

The OOB allgather code expects each caller process to pass in its rank, based on the API. But the current implementation simply passes "0" for all processes. This worked fine so far because none of the application codes used that value, but it could break a future code that relies on that parameter.

Signed-off-by: Pavan Balaji pavanbalaji.work@gmail.com

[pavanbalaji]

Hi @Sergei-Lebedev or @bureddy: Is this ready to be merged into master?

[bureddy]

@Sergei-Lebedev can you merge?

[Sergei-Lebedev]

@pavanbalaji pls rebase and I will merge

[pavanbalaji]

@pavanbalaji pls rebase and I will merge

@Sergei-Lebedev Done.