Fix undefined extra_rcparams

Author: astrofrog

pytest_mpl/plugin.py

@@ -555,6 +555,8 @@ def save_figure(self, item, fig, filename):
 
         original_source_date_epoch = os.environ.get('SOURCE_DATE_EPOCH', None)
 
+        extra_rcparams = {}
+
         if deterministic:
 
             # Make sure we don't modify the original dictionary in case is a common
@@ -566,8 +568,6 @@ def save_figure(self, item, fig, filename):
 
             ext = self._file_extension(item)
 
-            extra_rcparams = {}
-
             if ext == 'png':
                 extra_metadata = {"Software": None}
             elif ext == 'pdf':