Added additional names for scalapack and blacs related libs on ubuntu 14...

Hi!
Recently, I installed deal.ii on my ubuntu 14.04 machine and the cmake configure system did not pick up
the mumps library provided by ubuntu. A short digging revealed that this was caused by the mismatch of name suggestions in the FINDMUMPS.cmake and the names used on ubuntu.
Adding the correct names fixed the problem. So maybe this fix might be relevant to others, although I am not sure whether it is the right CMake way :)

The relevant packages on ubuntu are
libmumps-dev
libblacs-mpi-dev
libscalapack-mpi1