ICE on valid with allocatable class component

[Dominique Dhumieres]

This is a 4.7 regression introduced after r171100 and
before (or at) r171957 (r171654?). The backtrace is:

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000050
0x000000010011e8bf in gfc_sym_type (sym=0x141f21d00) at ../../work/gcc/fortran/trans-types.c:2112
2112	      if (sym->attr.optional || sym->ns->proc_name->attr.entry_master)
(gdb) bt
#0  0x000000010011e8bf in gfc_sym_type (sym=0x141f21d00) at ../../work/gcc/fortran/trans-types.c:2112
#1  0x000000010011dc45 in gfc_get_function_type (sym=0x1) at ../../work/gcc/fortran/trans-types.c:2674

gcc/fortran/trans-types.c has been changed in r171519 and 171949, but the changes
seem unrelated to the segmentation fault.

BTW when you find a problem, you should fill directly a pr in bugzilla without
being ashamed that it may be a duplicate;-)

Dominique