flake8 fix multiple spaces after operator.

Author: rouilj

roundup/cgi/templating.py

@@ -2141,7 +2141,7 @@ def field(self, labelfirst=False, y_label=None, n_label=None,
         if (labelfirst):
             s = u_label + u_rb + y_label + y_rb + n_label + n_rb
         else:
-            s = u_label + u_rb +y_rb + y_label +  n_rb + n_label
+            s = u_label + u_rb +y_rb + y_label + n_rb + n_label
 
         return s