Streams without meshfile set to "none" should die if mapalgo is set to anything besides "none".

The ciode in dshr_strdata_mod silently sets mapalgo to "none" whena mesh file isn't given

``` fortran
if (.not. ESMF_MeshIsCreated(stream_mesh)) then
sdat%stream(ns)%mapalgo = 'none'
else
```

This is problematic, because then the user thinks the code is properly doing a mapping -- when it really isn't.

I suggest that the code abort if mapgo is NOT none, so the user is informed that they can't do those two settings together.