Make one function in packaging.metadata simpler

Lib/packaging/metadata.py

@@ -185,6 +185,7 @@ _MISSING = object()
 
 _FILESAFE = re.compile('[^A-Za-z0-9.]+')
 
+
 class Metadata:
     """The metadata of a release.
 
@@ -228,10 +229,8 @@ class Metadata:
 
     def __delitem__(self, name):
         field_name = self._convert_name(name)
-        try:
-            del self._fields[field_name]
-        except KeyError:
-            raise KeyError(name)
+        # we let a KeyError propagate
+        del self._fields[field_name]
         self._set_best_version()
 
     def __contains__(self, name):