BUG: Fix trivial bug in mask largest connect component.
BUG: Fix trivial bug in mask largest connect component.

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