Revert back to checking for name attribute only when debug flag is set. Never throw an exception here. Fixes #621

Revert "Improve error handling when no element is missing its name attribute. Still need to set debug flag to see exception."

This reverts commit 22edeaf28f25352df46cb7fe992506d62f9a134d.
Merge branch 'master' of github.com:jzaefferer/jquery-validation