Adding ability to run tests without libmesh configuration.

This code adds a way for a code to ignore errors when finding options.
This would solve issue #4153 
If there is a better way to push the option into util.py, I can rewrite that portion.

A code can now do something like:
argv = sys.argv[:]
argv.append('--ignore-option-errors')
TestHarness.buildAndRun(argv, app_name, MOOSE_DIR)

to ignore the option errors.