FIX: Skip refcheck in ArraySequence construction/extension

[arokem]

I stumbled into this in the course of my work on pyAFQ.

For testing, part of the code reads data from a trk file. This seems to cause some issues in this method, but only on 3.7: https://travis-ci.org/arokem/pyAFQ/jobs/483151878. Unfortunately, I was not able to reproduce these errors locally on my machine...

After reading about what this might be, and implementing the proposed change, these tests are now passing on the Travis build for that branch, though.

Any objections to this?

[coveralls]

Coverage remained the same at 91.812% when pulling 872ce94 on arokem:array_sequence_resize into f9e7670 on nipy:master.

[codecov-io]

Codecov Report

Merging #719 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master    #719   +/-   ##
======================================
  Coverage    89.1%   89.1%           
======================================
  Files          93      93           
  Lines       11468   11468           
  Branches     1991    1991           
======================================
  Hits        10218   10218           
  Misses        911     911           
  Partials      339     339

Impacted Files	Coverage Δ
nibabel/streamlines/array_sequence.py	100% <100%> (ø)	⬆️

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[effigies]

Okay, I've looked through this file, and tried to think through the ways that you might hit this function, and it seems like the ndarray object should be pretty isolated, so the refcount doesn't seem to be going up for a reason we need to guard against.

So I'm inclined to merge.

@matthew-brett @MarcCote This is in code you two co-wrote, so if you see a reason we need to seriously worry about breaking other objects sharing a buffer, then please make some noise.

I'll plan to merge on Friday.

[matthew-brett]

I defer to @MarcCote on this one ...

[MarcCote]

After looking at the resize documentation, I'd say let's merge this. It should be fine.

[effigies]

Thanks for the review.