Fix crash when FileCache.delete() is called on non-existing file.

Author: sybrenstuvel

cachecontrol/caches/file_cache.py

@@ -104,7 +104,10 @@ def set(self, key, value):
     def delete(self, key):
         name = self._fn(key)
         if not self.forever:
-            os.remove(name)
+            try:
+                os.remove(name)
+            except FileNotFoundError:
+                pass
 
 
 def url_to_file_path(url, filecache):