Fixes #503; raise InternalServerError works now.
Fixes #503; raise InternalServerError works now.

http://merb.lighthouseapp.com/projects/7433/tickets/503

InternalServerError's (ISE's) used to be 'special' in a previous
release.  They aren't special anymore.

We should add a spec in addition to this change.  I looked over
the specs and I'm not sure where a spec should go.

merb/merb,wycats/merb,merb/merb,wycats/merb,wycats/merb,wycats/merb,wycats/merb,merb/merb