Make Geppetto work with httpcommons 4.1

This "downgrades" Geppetto so that it can play nicely with the
Eclipse IDE with respect to org.apache.httpcommons plug-ins.
Apparently, the ones bundled with the IDE (even in Kepler) has still
not been upgraded from version 4.1. This means that the HttpPatch
class is not included and must be faked.