don't attempt to normalize the rotation vector

indeed, by construction of the rotation matrix, it is
guaranteed to have a length of 1.

moreover, the normalization code was missing a square-root,
fortunatelly, since the length is 1, this didn't cause any
damage (since sqrt(1) = 1).

Change-Id: I9facd668caaf5bb3bfccb139ab872f2bb2066365