Options: Fix restoring last page for "delayed" created categories
Options: Fix restoring last page for "delayed" created categories

E.g. when opening Designer > Forms, restarting Qt Creator and opening
options dialog again.

Change-Id: I0cfabed8c9e7ef8c98abab5490181223558e21a2
Reviewed-by: Christian Stenger <accbb51712d7b9c4fb108439d01e716148e5f9e6@digia.com>

kuba1/qtcreator,farseerri/git_code,martyone/sailfish-qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator,Distrotech/qtcreator,martyone/sailfish-qtcreator,kuba1/qtcreator,Distrotech/qtcreator,danimo/qt-creator,maui-packages/qt-creator,xianian/qt-creator,xianian/qt-creator,xianian/qt-creator,kuba1/qtcreator,maui-packages/qt-creator,kuba1/qtcreator,xianian/qt-creator,farseerri/git_code,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,danimo/qt-creator,amyvmiwei/qt-creator,amyvmiwei/qt-creator,kuba1/qtcreator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,kuba1/qtcreator,AltarBeastiful/qt-creator,farseerri/git_code,AltarBeastiful/qt-creator,Distrotech/qtcreator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,xianian/qt-creator,farseerri/git_code,maui-packages/qt-creator,danimo/qt-creator,xianian/qt-creator,danimo/qt-creator,amyvmiwei/qt-creator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,farseerri/git_code,AltarBeastiful/qt-creator,AltarBeastiful/qt-creator,maui-packages/qt-creator,Distrotech/qtcreator,Distrotech/qtcreator,AltarBeastiful/qt-creator,danimo/qt-creator,Distrotech/qtcreator,farseerri/git_code,maui-packages/qt-creator,martyone/sailfish-qtcreator,maui-packages/qt-creator,xianian/qt-creator,danimo/qt-creator,AltarBeastiful/qt-creator,kuba1/qtcreator,xianian/qt-creator,danimo/qt-creator,farseerri/git_code,farseerri/git_code,danimo/qt-creator,kuba1/qtcreator,Distrotech/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,amyvmiwei/qt-creator,maui-packages/qt-creator