Fix a compiler lack of initialization warning. While passing an invalid QML path seems to be fine[1], getting rid of the warning is nice anyway.

[1] fine in terms of Mudlet not crashing. You get a white thing instead with a successful return value - it should do nothing and return false + the error message explaining that the QML file wasn't found at the location provided (include the location too, so users know what they passed when they're constructing a dynamic path).