Change compilers in paths to uppercase for external cray packages

[NMannall]

The cray compiler wrappers can break if the prefix paths for external packages use lowercase compiler names.

To replicate the current error, you can run:

module load PrgEnv-gnu
module load other-software
module load spack
spack install cray-mpich
spack load cray-mpich
ftn hello.F90

Where hello.F90 is a simple test program:

program hello
  use mpi

  print *, 'Hello, World!'
end program hello