Guard Kernel.#catch without block from segfault

[kachick]

☻  bin/topaz -e 'catch :s'
[1]    36899 segmentation fault  bin/topaz -e 'catch :s'

last of untranslated

File "topaz/modules/kernel.py", line 441, in method_catch
  return space.invoke_block(block, [])
File "topaz/objspace.py", line 648, in invoke_block
  bc = block.bytecode
AttributeError: 'NoneType' object has no attribute 'bytecode'

ruby-1.9.3p551

☻  ruby -e 'catch :s'
-e:1:in `catch': no block given (LocalJumpError)