Tests are failing on Ubuntu 12.04

Created by: tiagofrepereira2012

Unit tests are failing on Ubuntu 12.04 (https://gitlab.idiap.ch/biometric/bob.nightlies/builds/2968) Basically the function numpy.full does not exists in numpy 1.6 (the default for the ubuntu 12.04). The function is available since numpy 1.8.

For example, I would suggest to replace the code

numpy.full((1,len(probes)), numpy.nan, numpy.float64)

to

numpy.ones((1,len(probes)), numpy.float64) * numpy.nan