TEST/STY: Travis errors

[effigies]

Fixes some Travis issues.

[coveralls]

Coverage remained the same at 96.254% when pulling d0c9e36 on effigies:fix/travis into b2c0f81 on nipy:master.

[codecov-io]

Codecov Report

Merging #568 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #568   +/-   ##
=======================================
  Coverage   94.32%   94.32%           
=======================================
  Files         177      177           
  Lines       24691    24691           
  Branches     2638     2638           
=======================================
  Hits        23290    23290           
  Misses        925      925           
  Partials      476      476

Impacted Files	Coverage Δ
nibabel/ecat.py	85.79% <100%> (ø)	⬆️
nibabel/tripwire.py	100% <100%> (ø)	⬆️
nibabel/tests/test_image_api.py	99.04% <100%> (ø)	⬆️

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[effigies]

@matthew-brett These are minor fixes. Plan to merge tomorrow AM, unless you have objections.