config: remove ruby_fs.py

config: remove ruby_fs.py

The patch removes the ruby_fs.py file.  The functionality is being moved to
fs.py.  This would being ruby fs simulations in line with how ruby se
simulations are started (using --ruby option).  The alpha fs config functions
are being combined for classing and ruby memory systems.  This required
renaming the piobus in ruby to iobus.  So, we will have stats being renamed
in the stats file for ruby fs regression.