Revert "msvc doesn't understand -Wl,-rpath option"

This reverts commit cc639be5d0cad72a4da3fd9f667a83d939fc4d1c.

This shouldn't be done on the platform, but on the compiler. Anyway,
we won't make GPU op link to BLAS in Pylearn2 for now, so I just
remove this.
Merge pull request #1360 from nouiz/revert_blas_windows

Revert "msvc doesn't understand -Wl,-rpath option"