Noticed use of uninitialized value when built vcmi with -fsanitize=undefined:
```
Established connection with
VCMI 0.99 b310f2e61e (server).
UUID: bab9a90d-7416-4566-8817-e367ffcac7c1
../vcmi-9999/client/lobby/SelectionTab.cpp:138:16:
runtime error: load of value 32717, which is not a valid value for type 'ESortBy'
/usr/lib/gcc/x86_64-pc-linux-gnu/12.0.0/include/g++-v12/tuple:190:4:
runtime error: load of value 32717, which is not a valid value for type 'ESortBy'
/usr/lib/gcc/x86_64-pc-linux-gnu/12.0.0/include/g++-v12/tuple:190:4:
runtime error: load of value 32717, which is not a valid value for type 'ESortBy'
```
Here (before the change) `SelectionTab()` used `generalSortingBy` before
first use:
```
SelectionTab::SelectionTab(ESelectionScreen Type) {
...
if(tabType != ESelectionScreen::campaignList)
{
...
ESortBy criteria = (ESortBy)i;
if(criteria == _name)
criteria = generalSortingBy;
buttonsSortBy.push_back(... std::bind(&SelectionTab::sortBy, this, criteria)));
...
}
...
switch(tabType)
{
case ESelectionScreen::newGame:
generalSortingBy = ESortBy::_name;
....
```
The change moves `generalSortingBy` initialization before first use.
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>