New util's function validate_hash_conf allows you to programmatically reload
swift.conf and hash path global vars HASH_PATH_SUFFIX and HASH_PATH_PREFIX
when they are invalid.
When you load swift.common.utils before you have a swift.conf there's no good
way to force a re-read of swift.conf and repopulate the hash path config
options - short of restarting the process or reloading the module - both of
which are hard to unittest. This should be no worse in general and in some
cases easier.
Change-Id: I1ff22c5647f127f65589762b3026f82c9f9401c1