ss_nn_MUDFLAT: correct branch name

src/futils/getm_version.F90

 module getm_version
    character(len=*),parameter :: git_commit_id = "2.5.0"
-   character(len=*),parameter :: git_branch_name = "cfl"
+   character(len=*),parameter :: git_branch_name = "ss_nn_MUDFLAT"
 end module