Bug fix, was triggering an error in the command line edit window (ie. th...

...e window you get by hitting c-f in command line) after not moving the cursor for a few seconds (ie. when CursorHold event is fired)

Not sure if everyone else is getting this error, but before this fix every time I tried editing something in the command line edit window I'd get the error 'undefined variable: b:ycm_changedtick' as well as a bunch of other errors.