removed inconsistent fields method (JuliaArrays#18)

Author: Pietro Vertechi

src/structarray.jl

@@ -70,7 +70,6 @@ end
 Base.@propagate_inbounds Base.setindex!(s::StructArray, val, I::Int...) = set_ith!(s, val, I...)
 
 fields(::Type{<:NamedTuple{K}}) where {K} = K
-fields(::Type{<:StructArray{T}}) where {T} = fields(T)
 @generated function fields(t::Type{T}) where {T}
    return :($(Expr(:tuple, [QuoteNode(f) for f in fieldnames(T)]...)))
 end