BF: apply correct fix to quartile test
BF: apply correct fix to quartile test

I applied half of the fix in the previous commit by getting confused
with a git stash

bthirion/nipy,alexis-roche/register,bthirion/nipy,nipy/nipy-labs,arokem/nipy,bthirion/nipy,alexis-roche/nireg,nipy/nireg,arokem/nipy,alexis-roche/nipy,alexis-roche/nipy,nipy/nipy-labs,alexis-roche/register,arokem/nipy,alexis-roche/nipy,alexis-roche/niseg,arokem/nipy,nipy/nireg,alexis-roche/register,alexis-roche/nipy,bthirion/nipy,alexis-roche/niseg,alexis-roche/nireg