give back flann on mipsel

[Mathieu Malaterre <malat@debian.org>]

I do not see why it failed previously [1], so please give back flann on mipsel:

 gb flann_1.8.4-2 . mipsel

thanks

[1] https://buildd.debian.org/status/fetch.php?pkg=flann&arch=mipsel&ver=1.8.4-2&stamp=1383300519