Bug 404174

SUMMARY
The CSV importer crashes on the column selection page when entered a second time.

STEPS TO REPRODUCE
1. Select File/Import/CSV
2. Select banking profile (must exist)
3. Select a file
4. Press next until you reach the column selection page
5. Press back until you reach the profile selection page
6. Repeat steps 2-4

OBSERVED RESULT
Upon reaching the column selection the second time the wizard crashes

EXPECTED RESULT
Don't crash and work like normal

ADDITIONAL INFORMATION
Navigating back only to the separator selection page and going forward from there does not cause the crash. One has to go back until the profile selection page is shown.

I found the problem by accident when working on bug #404156. The changes made to solve bug #404156 are not related to the crash. The problem is in the code probably for a long time already but nobody stepped on it yet.

Here's a backtrace:
#0  0x00007fffc3b85da5 in qMapLessThanKey<Column>(Column const&, Column const&)
    (key1=<error reading variable>, key2=@0x93154dc: Column::Number)
    at /usr/include/qt5/QtCore/qmap.h:71
#1  0x00007fffc3b85d5c in QMapNode<Column, int>::lowerBound(Column const&)
    (this=0x8d3e640, akey=@0x93154dc: Column::Number)
    at /usr/include/qt5/QtCore/qmap.h:155
#2  0x00007fffc3b8410a in QMapData<Column, int>::findNode(Column const&) const
    (this=0x7fffd000ae60, akey=@0x93154dc: Column::Number)
    at /usr/include/qt5/QtCore/qmap.h:287
#3  0x00007fffc3b82602 in QMap<Column, int>::value(Column const&, int const&) const
    (this=0x7fffd000a228, akey=@0x93154dc: Column::Number, adefaultValue=@0x7fffffffb6a0: 0) at /usr/include/qt5/QtCore/qmap.h:648
#4  0x00007fffc3b876dd in BankingPage::initializePage() (this=0x88ff4a0)
    at /home/thb/devel/kmymoney/kmymoney/plugins/csv/import/bankingwizardpage.cpp:93
#5  0x00007ffff3045fc7 in  () at /usr/lib64/libQt5Widgets.so.5
#6  0x00007ffff30461c3 in QWizard::next() () at /usr/lib64/libQt5Widgets.so.5
#7  0x00007ffff0ea204a in QMetaObject::activate(QObject*, int, int, void**) ()
    at /usr/lib64/libQt5Core.so.5
#8  0x00007ffff2f1ee62 in QAbstractButton::clicked(bool) ()
    at /usr/lib64/libQt5Widgets.so.5
#9  0x00007ffff2f1f04a in  () at /usr/lib64/libQt5Widgets.so.5
#10 0x00007ffff2f2036a in  () at /usr/lib64/libQt5Widgets.so.5
#11 0x00007ffff2f20535 in QAbstractButton::mouseReleaseEvent(QMouseEvent*) ()
    at /usr/lib64/libQt5Widgets.so.5