Qt: Fix uninitialized memory access in val_units_

Fixes the following UBSAN errors:

    ui/qt/io_graph_dialog.cpp:1720:75: runtime error: load of value 3200171710, which is not a valid value for type 'io_graph_item_unit_t'
        #0 0x5611f0b0cd1d in IOGraph::setFilter(QString const&) ui/qt/io_graph_dialog.cpp:1720:75
        #1 0x5611f0b737a1 in IOGraph::IOGraph(QCustomPlot*) ui/qt/io_graph_dialog.cpp:1682:5
        #2 0x5611f0afb3f3 in IOGraphDialog::addGraph(bool, QString, QString, int, IOGraph::PlotStyles, io_graph_item_unit_t, QString, int) ui/qt/io_graph_dialog.cpp:340:24
        #3 0x5611f0af7c19 in IOGraphDialog::IOGraphDialog(QWidget&, CaptureFile&) ui/qt/io_graph_dialog.cpp:289:13

    ui/qt/io_graph_dialog.cpp:1818:19: runtime error: load of value 3200171710, which is not a valid value for type 'io_graph_item_unit_t'
        #0 0x5611f0b1167e in IOGraph::setPlotStyle(int) ui/qt/io_graph_dialog.cpp:1818:19
        #1 0x5611f0b062ee in IOGraphDialog::syncGraphSettings(QTreeWidgetItem*) ui/qt/io_graph_dialog.cpp:420:10

    ui/qt/io_graph_dialog.cpp:1872:29: runtime error: load of value 3200171710, which is not a valid value for type 'io_graph_item_unit_t'
        #0 0x5611f0b13e6a in IOGraph::setValueUnits(int) ui/qt/io_graph_dialog.cpp:1872:29
        #1 0x5611f0b06640 in IOGraphDialog::syncGraphSettings(QTreeWidgetItem*) ui/qt/io_graph_dialog.cpp:422:10

Note that calling setFilter with an empty string is pretty useless,
especially since the filter is initialized later, so remove it.
The choice for IOG_ITEM_UNIT_FIRST is quite arbitrary and needed because
setValueUnits reads the "old" (uninitialized) value.

Change-Id: I32c65a30593cb718b838c0f324e0d1b0eaab90e5
Reviewed-on: https://code.wireshark.org/review/20767
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>

0 files changed, 0 insertions, 0 deletions