-display accepts "none[a-z,0-9]*" instead of 'none'

When using the '-display' option the parameter 'none' is not the only string that causes the behaviour of 'none'. I can use '-display noneMICKEYMOUSE' and still have the none behaviour.

Fixed in:

https://git.qemu.org/?p=qemu.git;a=commitdiff;h=2c9498c3e44cd5574