Roi GET unexpectedly returns status 206

[stuarteberg]

For unknown reasons, DVID often returns status 206 in response to a ROI query instead of the expected status 200. The body text appears to be correct, so one can naively ignore the strange status and still get the right answer in such cases.

Here's an example of one such query:

GET http://emdata1.int.janelia.org/api/node/22c0f/alpha3and2/roi

(FWIW, that returns a json list with 15523 run-encodings in the form [z,y,x0,x1], which translate to 766038 blocks).