Suppress FSL warnings in .travis.yml output

Author: Ben Cipollini

.travis.yml

@@ -37,7 +37,7 @@ install:
 - pip install https://github.com/trungdong/prov/archive/rdf.zip
 - python setup.py install
 script:
-- nosetests --with-doctest --with-cov --cov nipype --cov-config .coveragerc --logging-level=INFO
+- python -W once:FSL:UserWarning:nipype `which nosetests` --with-doctest --with-cov --cover-package nipype --cov-config .coveragerc --logging-level=INFO
 after_success:
 - coveralls --config_file .coveragerc
 deploy: