Revert part of 466ce5fc88546baf75dc9e9dead5e1d6af6fd721

We no longer need it to speed things up in trunk, and this way is
actually a bit faster now.

After    | File Name                                  | Before   || Change
-----------------------------------------------------------------------------
0m59.89s | Total                                      | 1m06.73s || -0m06.84s
-----------------------------------------------------------------------------
0m35.71s | categories/Pseudofunctor/RewriteLaws       | 0m42.32s || -0m06.60s
0m21.89s | categories/Grothendieck/PseudofunctorToCat | 0m22.15s || -0m00.25s
0m00.77s | contrib/HoTTBook                           | 0m00.75s || +0m00.02s
0m00.65s | categories/categories                      | 0m00.68s || -0m00.03s
0m00.27s | categories/Grothendieck/Grothendieck       | 0m00.28s || -0m00.01s
0m00.22s | categories/DependentProduct                | 0m00.20s || +0m00.01s
0m00.20s | categories/Grothendieck/ToCat              | 0m00.20s || +0m00.00s
0m00.18s | categories/Pseudofunctor/Pseudofunctor     | 0m00.16s || +0m00.01s
Merge pull request #413 from JasonGross/revert-pseudofunctor-change

Revert part of 466ce5fc88546baf75dc9e9dead5e1d6af6fd721