Xgboost: Unable clone help!

[jeehyun100]

For bugs or installation issues, please provide the following information.
The more information you provide, the more easily we will be able to offer
help and advice.

Environment info

Operating System:
ubuntu 16.04
Compiler:

Package used (python/R/jvm/C++):

xgboost version used:

If installing from source, please provide

1. The commit hash (git rev-parse HEAD)
   4f7fb12585dfee57c7cb5bd7abd13f6a939aaa06
2. Logs will be helpful (If logs are large, please upload as attachment).
   remote: Counting objects: 3142, done.
   remote: Total 3142 (delta 0), reused 0 (delta 0), pack-reused 3142
   Receiving objects: 100% (3142/3142), 900.20 KiB | 430.00 KiB/s, done.
   Resolving deltas: 100% (2039/2039), done.
   Checking connectivity... done.
   Submodule path 'rabit': checked out 'a764d45cfb438cc9f15cf47ce586c02ff2c65d0f'
   Unable to checkout 'f3937a96fdec78a73446aaaa114c112ff31f5503' in submodule path 'cub'

If you are using python package, please provide

1. The python version and distribution : 3.5
2. The command to install xgboost if you are not installing from source

Steps to reproduce

1. git clone --recursive https://github.com/dmlc/xgboost
   Submodule path 'dmlc-core': checked out 'b5bec5481df86e8e6728d8bd80a61d87ef3b2cd5'
   Cloning into 'nccl'...
   remote: Counting objects: 652, done.
   remote: Total 652 (delta 0), reused 0 (delta 0), pack-reused 652
   Receiving objects: 100% (652/652), 1.38 MiB | 493.00 KiB/s, done.
   Resolving deltas: 100% (411/411), done.
   Checking connectivity... done.
   Submodule path 'nccl': checked out '018ff75f78e4d3616051fdcd3da7cf64249b6d59'
   Cloning into 'rabit'...
   remote: Counting objects: 3142, done.
   remote: Total 3142 (delta 0), reused 0 (delta 0), pack-reused 3142
   Receiving objects: 100% (3142/3142), 900.20 KiB | 430.00 KiB/s, done.
   Resolving deltas: 100% (2039/2039), done.
   Checking connectivity... done.
   Submodule path 'rabit': checked out 'a764d45cfb438cc9f15cf47ce586c02ff2c65d0f'
   Unable to checkout 'f3937a96fdec78a73446aaaa114c112ff31f5503' in submodule path 'cub'

[RAMitchell]

Should be fixed in #2591

[earthling4]

This doesn't seem to be fixed. Seeing this now