bug 1411089: Remove unneeded exception handling
bug 1411089: Remove unneeded exception handling

This exception handling was added for bug 875780, to catch errors when
the document html was empty. With our current parsing stack, empty
documents do not raise an error, just return no tokens, so we don't need
to catch any exceptions.

jwhitlock/kuma,escattone/kuma,a2sheppy/kuma,mozilla/kuma,Elchi3/kuma,SphinxKnight/kuma,SphinxKnight/kuma,SphinxKnight/kuma,mozilla/kuma,a2sheppy/kuma,a2sheppy/kuma,escattone/kuma,SphinxKnight/kuma,Elchi3/kuma,a2sheppy/kuma,jwhitlock/kuma,mozilla/kuma,SphinxKnight/kuma,Elchi3/kuma,jwhitlock/kuma,mozilla/kuma,jwhitlock/kuma,SphinxKnight/kuma,jwhitlock/kuma,mozilla/kuma,a2sheppy/kuma,escattone/kuma,Elchi3/kuma,Elchi3/kuma