Revert "xserver: Fix a typo"
This reverts commit 427f8bc0. When receiving an output update for the mode size we need to rotate the stored width and height values if and only if we have an xdg-output for this output since in this case the stored values describe the output's size in logical space, i.e. rotated. The here reverted commit made a code change with which we would not rotate though when an xdg-output was available since in this case the need_rotate variable was set to False what caused in the check afterwards the first branch to execute.