1. Blank parameters were listed as being of "No Value", and when you hit
"set parameters" this string replaced the empty string in the database,
not exactly what you want. I changed the code to leave the input box
blank.
2. caching of empty parameter strings didn't work. I'd fixed this earlier
for ad_parameter proper but missed the fact that ad_parameter_cache had
the same bug.
With these changes you can now run acs-workflow's admin UI without graphviz
