Restore the last-used color only on startup

We save the last used color only on application exit, when the
KisViewManager object is deleted, so we should only read the option
on creating the KisViewManager, not every time we create a new
view.

BUG:394816
(cherry picked from commit 11eaaf3538b2936bd4d6aaf9f3ca638df72981a7)