COMP: Update SWIG to 2.0.12

Should fix the warnings on the Fedora-19-x86_64_WrapITK dashboard machine.
There are 761 of these errors :
warning: variable 'md' set but not used [-Wunused-but-set-variable]
   PyObject *m, *d, *md;

The bug was fixed here:
https://sourceforge.net/p/swig/bugs/1246/

Change-Id: I86a0f2e811d1b079a308caf20093475f8b9e23b4
Merge topic 'Update-SWIG'

bfad2da1 COMP: Update SWIG to 2.0.12