[style] fix shadowed import name 'errno' from outer scope

Author: Pierre-Sassoulas

src/_pytest/_py/error.py

@@ -90,15 +90,14 @@ def checked_call(
         except OSError as value:
             if not hasattr(value, "errno"):
                 raise
-            errno = value.errno
             if sys.platform == "win32":
                 try:
-                    cls = self._geterrnoclass(_winerrnomap[errno])
+                    cls = self._geterrnoclass(_winerrnomap[value.errno])
                 except KeyError:
                     raise value
             else:
                 # we are not on Windows, or we got a proper OSError
-                cls = self._geterrnoclass(errno)
+                cls = self._geterrnoclass(value.errno)
 
             raise cls(f"{func.__name__}{args!r}")