Skip collectors and handlers with syntax errors.

As per https://github.com/BrightcoveOS/Diamond/wiki/Installation, Diamond
supports Python 2.4+, but the kafka and jcollectd collectors break
compatibility. This change handles treats syntax errors the same as import
errors so that the server can run without incompatible collectors and handlers
on systems with older versions of Python.

Caveat: this fix only works if the core server code keeps compatibility with
Python 2.4.

Addresses BrightcoveOS/Diamond#444