trans-decl.c, [...]: Replace all occurences of 'gfc_strlen_type_node' by 'gfc_charlen_type_node'.

fortran/
* trans-decl.c, trans-expr.c, trans-io.c, trans-types.c: Replace
all occurences of 'gfc_strlen_type_node' by
'gfc_charlen_type_node'.
* trans-types.h: Same. Also update comment accordingly.

libgfortran/
* libgfortran.h: Replace 'gfc_strlen_type' by
'gfc_charlen_type'. Update comment accordingly.
* intrinsics/args.c, intrinsics/env.c, io/io.h, io/transfer.c:
Replace all occurences of 'gfc_strlen_type' by 'gfc_charlen_type'.

From-SVN: r86828