Broadcasting into `DistributedArray`s broken in 0.6.8

[devmotion]

The following example is broken in DistributedArrays@0.6.8:

julia> addprocs(4);

julia> dv = distribute(rand(40));

julia> dv .= ones(40);
ERROR: TypeError: in DArrayStyle, in Style, expected Style<:Base.Broadcast.BroadcastStyle, got Type{Nothing}
Stacktrace:
 [1] bcdistribute
   @ ~/.julia/packages/DistributedArrays/Ve8lp/src/broadcast.jl:122 [inlined]
 [2] copyto!
   @ ~/.julia/packages/DistributedArrays/Ve8lp/src/broadcast.jl:68 [inlined]
 [3] copyto!
   @ ./broadcast.jl:947 [inlined]
 [4] materialize!
   @ ./broadcast.jl:905 [inlined]
 [5] materialize!(dest::DArray{…}, bc::Base.Broadcast.Broadcasted{…})
   @ Base.Broadcast ./broadcast.jl:902
 [6] top-level scope
   @ REPL[21]:1
Some type information was truncated. Use `show(err)` to see complete types.

julia> dv[1]
0.9960399912849884

julia> dv .= @view(zeros(50)[11:end]);
ERROR: TypeError: in DArrayStyle, in Style, expected Style<:Base.Broadcast.BroadcastStyle, got Type{Nothing}
Stacktrace:
 [1] bcdistribute
   @ ~/.julia/packages/DistributedArrays/Ve8lp/src/broadcast.jl:122 [inlined]
 [2] copyto!
   @ ~/.julia/packages/DistributedArrays/Ve8lp/src/broadcast.jl:68 [inlined]
 [3] copyto!
   @ ./broadcast.jl:947 [inlined]
 [4] materialize!
   @ ./broadcast.jl:905 [inlined]
 [5] materialize!(dest::DArray{…}, bc::Base.Broadcast.Broadcasted{…})
   @ Base.Broadcast ./broadcast.jl:902
 [6] top-level scope
   @ REPL[24]:1
Some type information was truncated. Use `show(err)` to see complete types.

julia> dv[1]
0.9960399912849884

On DistributedArrays@0.6.7 it gives:

julia> addprocs(4);

julia> dv = distribute(rand(40));

julia> dv .= ones(40);

julia> dv[1]
1.0

julia> dv .= @view(zeros(50)[11:end]);

julia> dv[1]
0.0