segmentation fault for buffer.copy() with no args

[timoxley]

To reproduce from the command line:

$ iojs -e "Buffer(10).copy()"
[1]    87376 segmentation fault  iojs -e "Buffer(10).copy()"

While this isn't valid input to copy, this should probably not segfault.

Tested on iojs 1.8.1. Same issue in node 0.12.2.

[trevnorris]

Have a patch coming.

[trevnorris]

Fixed by 5404cbc.