GitError - 'REQUIRE' does not exist

Using v0.6.0-dev.2635 (linux), I am getting this error when trying Pkg.add("pkg") or Pkg.checkout("pkg") with many packages. Is there a way to avoid it?

julia> Pkg.add(“Combinatorics”)
ERROR: GitError(Code:ENOTFOUND, Class:Tree, the path ‘REQUIRE’ does not exist in the given tree)
macro expansion at ./libgit2/error.jl:99 [inlined]
Base.LibGit2.GitUnknownObject(::Base.LibGit2.GitRepo, ::String) at ./libgit2/repository.jl:100
revparseid at ./libgit2/repository.jl:128 [inlined]
isfixed(::String, ::Base.LibGit2.GitRepo, ::Dict{VersionNumber,Base.Pkg.Types.Available}) at ./pkg/read.jl:67
#7 at ./pkg/read.jl:210 [inlined]
with(::Base.Pkg.Read.##7#8{Dict{String,Tuple{VersionNumber,Bool}}}, ::Base.LibGit2.GitRepo) at ./libgit2/types.jl:576
with(::Function, ::Type{Base.LibGit2.GitRepo}, ::String, ::Vararg{String,N} where N) at ./libgit2/types.jl:582
installed(::Dict{String,Dict{VersionNumber,Base.Pkg.Types.Available}}) at ./pkg/read.jl:208
resolve at ./pkg/entry.jl:480 [inlined]
edit(::Function, ::String, ::Base.Pkg.Types.VersionSet, ::Vararg{Base.Pkg.Types.VersionSet,N} where N) at ./pkg/entry.jl:30
(::Base.Pkg.Entry.##1#3{String,Base.Pkg.Types.VersionSet})() at ./task.jl:335
[1] sync_end() at ./task.jl:287
[2] macro expansion at ./task.jl:303 [inlined]
[3] add(::String, ::Base.Pkg.Types.VersionSet) at ./pkg/entry.jl:50
[4] (::Base.Pkg.Dir.##2#3{Array{Any,1},Base.Pkg.Entry.#add,Tuple{String}})() at ./pkg/dir.jl:31
[5] cd(::Base.Pkg.Dir.##2#3{Array{Any,1},Base.Pkg.Entry.#add,Tuple{String}}, ::String) at ./file.jl:69
[6] #cd#1(::Array{Any,1}, ::Function, ::Function, ::String, ::Vararg{Any,N} where N) at ./pkg/dir.jl:31
[7] add(::String) at ./pkg/pkg.jl:102

Try a newer 0.6-dev version.

OK, when it is released – the version I am using is 1 day old.
Version 0.6.0-dev.2635 (2017-02-13 07:46 UTC)
Commit dc2459d (1 day old master)

That commit was from inside a pull request branch so its parents are a week old and don’t include a number of bugfixes and other recent changes.