Bumped ralph submodule dependency.  Previously, speculation was
allowed through calls on get_val and set_val on internal variables.
However, many calls on lists and maps did not use these.  For
instance, accessing the size of a list bypassed get_val (using
acquire_read_lock instead).  Changed interface so that speculation
happens and acquire_read_lock and acquire_write_lock instead of on
get_val/set_val.
Minor re-work.  Going to allow speculation test to load many rules into ftable first and then add and remove entries.  These changes lay groundwork for this update by not adding/removing depending on existing ftable size.
Allowing speculation test runner to specify the number of entries to
preload in flow table.