FIX: CI issues

[effigies]

Trying to figure out what's going on with #3261. Possibly xenial is being relegated to slow machines?

Also found a small bug while looking at the Travis outputs.

[codecov]

Codecov Report

Merging #3262 into master will increase coverage by 0.83%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3262      +/-   ##
==========================================
+ Coverage   64.23%   65.06%   +0.83%     
==========================================
  Files         300      302       +2     
  Lines       39884    39949      +65     
  Branches     5276     5282       +6     
==========================================
+ Hits        25618    25994     +376     
+ Misses      13210    12885     -325     
- Partials     1056     1070      +14     

Flag	Coverage Δ
#unittests	65.06% <100.00%> (+0.83%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
nipype/algorithms/misc.py	45.24% <100.00%> (+0.11%)	⬆️
nipype/pipeline/plugins/legacymultiproc.py	65.68% <0.00%> (-1.97%)	⬇️
nipype/__init__.py	53.19% <0.00%> (ø)
nipype/testing/__init__.py	88.88% <0.00%> (ø)
nipype/interfaces/base/core.py	84.22% <0.00%> (+0.36%)	⬆️
nipype/utils/filemanip.py	72.94% <0.00%> (+0.47%)	⬆️
nipype/interfaces/spm/preprocess.py	50.44% <0.00%> (+0.88%)	⬆️
nipype/pipeline/engine/utils.py	74.48% <0.00%> (+0.91%)	⬆️
nipype/interfaces/freesurfer/model.py	64.19% <0.00%> (+1.12%)	⬆️
nipype/pipeline/engine/nodes.py	78.63% <0.00%> (+1.26%)	⬆️
... and 13 more

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[effigies]

I guess this worked? Merging to see if master starts acting right.