Fix test and loading of filetypes, closes #577

doc/ft-csv.txt

@@ -1115,6 +1115,11 @@ manually, use: >
 to let the comma be the delimiter. This sets the buffer local delimiter
 variable b:delimiter.
 
+You can also set default delimiter to prevent a warning if no delimiter can
+be detected: >
+
+    :let g:csv_default_delim=','
+
 If your file does not consist of delimited columns, but rather is a fixed
 width csv file, see |csv-fixedwidth| for configuring the plugin appropriately.