Deploy via branchless bundle failing.

We deploy via a bundle that does not have any tags or branches.  The issue is the addition of the "-b <branch>", shown in the outputs of each operation for two revisions below: 

v2.15.4 (does not work):

    git clone -b <branch> --depth 1 <bundle file> <destination>

v.2.14.2 (works)

    git clone --depth 1 <bundle file> <destination>  

I traced the problem for us to 6f84111.  
  
If we are deploying the master branch from a repo, v2.15.4 will attempt to clone branch master from the bundle, which does not work since the bundle is only a collection of refs.