__wine_vxd_open() has several bugs. If filenameW doesn't end in
".vxd", it is wrongly
allowed to be over 8 characters long. If it does end in ".vxd", then a
maximum length
filename, eg. "12345678.vxd", always gets misdetected as being too long, as:
"lstrlenW( filenameW ) >= ARRAY_SIZE(name) - 4"
becomes 12 >= 12.

Rather do the checks for maximum filename length when we detect the
filename format.
Signed-off-by: Damjan Jovanovic <damjan.jov@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>