xfreerdp: fix a possible re-size race condition

In case of server side initiated desktop resize it could happen that the
client was "scaling" even if smart-sizing was disabled. The reason for
this was that the "scaled" width and height was set when the X Configure
event arrived but not in xf_desktop_resize.
Merge pull request #2247 from bmiklautz/fix/resizing_race

xfreerdp: fix a possible re-size race condition