wireprototypes: fix exception handling code with a bad pytype suppression This goes back to f5fcf7123a92, and I suspect it was a misread of the error message is describes- the LHS of `.sorted()` is always bytes, and bytes didn't have this method in py2 either. The invalid names were already handled like this a few lines above. PyCharm flagged this, and it stood out after converting the zope interfaces to Protocol classes (which hasn't been published yet).