Crash in rdfa_complete_object_literal_triples() trying to access NULL plain literal

[msporny]

This was reported via raptor at http://bugs.librdf.org/mantis/view.php?id=408 which contains the datasets.html file as an attachment in case the file below doesn't work

$ wget http://logd.tw.rpi.edu/twc/drupaltest/datasets
$ mv datasets datasets.html

$ cat .git/refs/heads/master 
bcaae8b7e0e7d7b9d0f3e0580740bfc66b75757c

$ gdb --args tests/dist/rdfa2n3 $PWD/datasets.html
... lots and lots of output ...


   
  "eia-doe-gov net_generation"@en .

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000
0x000000010000886b in rdfa_complete_object_literal_triples (context=0x100108f90) at build/triple.c:446
446        else if(strlen(context->plain_literal) == 0)
(gdb) (gdb) p context->plain_literal
$1 = 0x0
(gdb) up
#1  0x000000010000611d in end_element (user_data=0x100100980, name=0x1001085c0 "td") at build/rdfa.c:936
936           rdfa_complete_object_literal_triples(context);

Looks like the end of a 'td' element?