fce83bd9f84883f93829e6ca9eacf098b018a02d in qtbase causes a crash:
setModel creates a new selection model, which calls currentChanged,
which accesses an uninitialized member. Hence, protect the access to it.

Change-Id: I144f40aa4286f1a9edba24519a30c08ff5091f57
Reviewed-by: hjk <hjk@theqtcompany.com>