Add unzip build-dep on Debian / Ubuntu systems

I missed the built-dep on unzip because my test machine happened to have it
installed; added to allow us to unpack the sources on these systems.

Signed-off-by: Daniel Pittman <daniel@rimspace.net>
Don't strip binaries on Debian systems

The binary content shipped with JRuby, etc, is already in "ready to go" state,
and we don't need an extra round of stripping.  This also avoids the situation
where an i386 box can't build because of amd64, or ARM, binary shlibs present
on disk.

Signed-off-by: Daniel Pittman <daniel@rimspace.net>