Make autogenerated role names 2–30 chars long

By default, `StringField` generates strings 1–30 chars long. However, role names
must be at least two characters long. Increase the minimum length of
auto-generated role names.
Merge pull request #1316 from Ichimonji10/role-name-len

Make autogenerated role names 2–30 chars long
Skip test which checks HTTP status code

After creating a product, an HTTP 200 status code is received. This is OK, but
an HTTP 201 status code is preferable. List `Product` as one of the entities
that is affected by bugzilla bug 1118015, thus skipping the relevant test.