comctl32: Rename the dwStyle and dwOldStyle variables in LISTVIEW_SetExtendedListViewStyle to more accurately reflect their purpose.

This also fixes local variable shadowing in the function, which should 
be avoided for purposes of code readability.

comctl32: Fix local variable shadowing in load_string by moving len to the block in which it is actually used.

shdocvw: The default value for the "CLSID\%CLSID_Internet" key isn't set on Windows, so we shouldn't set it either.