Remove requirement on Julia 0.3
Remove requirement on Julia 0.3

We do not need Julia 0.3 now that we determine the install directory at
build time.

pressel/MPI.jl,staticfloat/MPI.jl,JuliaPackageMirrors/MPI.jl,jkozdon/MPI.jl,JuliaParallel/MPI.jl