The Fortran compiler version detection infrastructure added by commit
v3.3.0-rc1~436^2~9 (Fortran: Add infrastructure to detect compiler
version, 2015-02-17) forgot to update CMakeFortranCompiler.cmake.in to
save the compiler version persistently as we do already in
"CMake{C,CXX}Compiler.cmake.in".  Add the missing line now.