Lower minimal length of search text

For languages like Chinese asking for more than two chars is ridiculous
(issue #335).

trans/forms.py

@@ -222,7 +222,7 @@ class SearchForm(forms.Form):
     # pylint: disable=C0103
     q = forms.CharField(
         label=_('Query'),
-        min_length=4,
+        min_length=2,
     )
     search = forms.ChoiceField(
         label=_('Search type'),

trans/tests/views.py

@@ -905,7 +905,7 @@ class SearchViewTest(ViewTestCase):
         # Short string
         self.do_search(
             {'q': 'x'},
-            'Ensure this value has at least 4 characters (it has 1).'
+            'Ensure this value has at least 2 characters (it has 1).'
         )
         # Wrong type
         self.do_search(