fix wrong Row number in DiscoveryDialog.py that caused following traceback:

Traceback (most recent call last):
File "/home/beremiz/beremiz/ProjectController.py", line 1536, in _Connect
dialog = DiscoveryDialog(self.AppFrame)
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 124, in __init__
self._init_ctrls(parent)
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 121, in _init_ctrls
self._init_sizers()
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 73, in _init_sizers
self._init_coll_ButtonGridSizer_Growables(self.ButtonGridSizer)
File "/home/beremiz/beremiz/dialogs/DiscoveryDialog.py", line 64, in _init_coll_ButtonGridSizer_Growables
parent.AddGrowableRow(1)
File "/usr/lib/python2.7/dist-packages/wx-3.0-gtk2/wx/_core.py", line 15343, in AddGrowableRow
return _core_.FlexGridSizer_AddGrowableRow(*args, **kwargs)
PyAssertionError: C++ assertion "!m_rows || idx < (size_t)m_rows" failed at ../src/common/sizer.cpp(1967) in AddGrowableRow(): invalid row index

     1

<?xml version="1.0"?>

     2

<purchaseOrder orderDate="1999-10-20">

     3

  <shipTo country="US">

     4

    <name>Alice Smith</name>

     5

    <street>123 Maple Street</street>

     6

    <city>Mill Valley</city>

     7

    <state>CA</state>

     8

    <zip>90952</zip>

     9

  </shipTo>

    10

  <billTo country="US">

    11

    <name>Robert Smith</name>

    12

    <street>8 Oak Avenue</street>

    13

    <city>Old Town</city>

    14

    <state>PA</state>

    15

    <zip>95819</zip>

    16

  </billTo>

    17

  <comment>Hurry, my lawn is going wild!</comment>

    18

  <items>

    19

    <item partNum="872-AA">

    20

      <productName>Lawnmower</productName>

    21

      <quantity>1</quantity>

    22

      <USPrice>148.95</USPrice>

    23

      <comment>Confirm this is electric</comment>

    24

    </item>

    25

    <item partNum="926-AA">

    26

      <productName>Baby Monitor</productName>

    27

      <quantity>1</quantity>

    28

      <USPrice>39.98</USPrice>

    29

      <shipDate>1999-05-21</shipDate>

    30

    </item>

    31

  </items>

    32

</purchaseOrder>