Remove unused variable somehow left in rL351132

[tamur]

Summary

Remove the unused variable oso_dwarf.

(For reasons I don't understand, the line SymbolFileDWARF *oso_dwarf; has stayed in the repository, although looking at https://reviews.llvm.org/rL351132#change-1JGlvWxNPgrh, the patch has removed it).

source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp

uint32_t SymbolFileDWARFDebugMap::FindTypes(
     const ConstString &name, const CompilerDeclContext *parent_decl_ctx,
     bool append, uint32_t max_matches,
     llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
     TypeMap &types) {
   if (!append)
     types.Clear();
 
   const uint32_t initial_types_size = types.GetSize();
-  SymbolFileDWARF *oso_dwarf;
 
   ForEachSymbolFile([&](SymbolFileDWARF *oso_dwarf) -> bool {
     oso_dwarf->FindTypes(name, parent_decl_ctx, append, max_matches,
                          searched_symbol_files, types);
     return types.GetSize() >= max_matches;
   });
 
   return types.GetSize() - initial_types_size;