Fonts with trailing spaces in their family names are incorrectly substituted

The commercial font Bonning Regular has a quirk in the way its family name is defined in the font: it is defined (possibly mistakenly) with a trailing space, i.e. as "Bonning " rather than as "Bonning".

Although Qt shows the font correctly in the font menu, when you actually choose the font from the menu, the drawn font ends up being substituted, and the desired font does not appear.

To reproduce the problem:

1. Install the Bonning Regular font.
2. Build and run the standard TextEdit example project.
3. Select some of the text in the default TextEdit document.
4. Choose "Bonning" from the font menu.

EXPECTED: The desired font should be used for the selected text.
ACTUAL: The font is substituted with a system font.