tools: fix option parsing in libinput measure
Missing '+' in the optstring caused it to evaluate all options. If any argument was passed to a subcommand, libinput-measure would throw an error and exit. https://bugs.freedesktop.org/show_bug.cgi?id=105246 Signed-off-by:Peter Hutterer <peter.hutterer@who-t.net> (cherry picked from commit 59550ed2)