fixed typo op.abspath to os.abspath

[fliem]

No description provided.

[coveralls]

Coverage decreased (-0.02%) to 70.46% when pulling 19eab7c on fliem:master into 5ca0086 on nipy:master.

[mwaskom]

You need to make this os.path.abspath, there isn't an os.abspath function.

I'm actually a little surprised the tests passed?

[satra]

this is inside list_outputs and is dependent on an input. the tests don't catch that (yet!).

@fliem - once you make the change @mwaskom suggested we can merge this.

[fliem]

Thanks @mwaskom. I changed it.
Best,
Franz