Log Message:
Fix the interpreter of event_rpcgen.py to point to a known Python binary.
This requires a dependency on Python.  Bump PKGREVISION to 1.

This is probably not the best solution: I guess it'd be nice to have a
libevent package that only included the binary libraries and no dependency
on Python, and another libevent-dev package with the event_rpcgen.py binary
and the Python dependency.  But this can be done later; I want to just fix
the breakage first.