Uncaught Exception dispalys error screen in CFME UI

https://bugzilla.redhat.com/show_bug.cgi?id=1133747

When the user enters an invalid,incomplete path in simulation
during parsing we get the Ruby URI::InvalidURIError. Caught this error
and converted it to MiqAeException::InvalidPathFormat
The Simuation UI code only catches this exception and throws up the
error window for others.
Merge pull request #477 from mkanoor/bugzilla_1133747

Uncaught Exception displays error screen in UI