Update _compat.py

add quote

flask_admin/_compat.py

@@ -38,7 +38,7 @@ if not PY2:
 
     # Various tools
     from functools import reduce
-    from urllib.parse import urljoin, urlparse
+    from urllib.parse import urljoin, urlparse, quote
 else:
     text_type = unicode
     string_types = (str, unicode)
@@ -62,6 +62,7 @@ else:
     # Helpers
     reduce = __builtins__['reduce'] if isinstance(__builtins__, dict) else __builtins__.reduce
     from urlparse import urljoin, urlparse
+    from urllib import quote
 
 
 def with_metaclass(meta, *bases):