Remove scale!{T<:BlasReal}(X::Array{T}, s::Complex)

* Reference: https://github.com/JuliaLang/julia/issues/1868#issuecomment-36004446
Fix scale(X::AbstractArray{Real}, s::Complex)

* after removal of corresponding scale! method
* also add tests
Merge pull request #5957 from JuliaLang/kms/fix_scale!

Remove scale!{T<:BlasReal}(X::Array{T}, s::Complex)