updated for version 7.4.314

Problem:    Completion messages can get in the way of a plugin.
Solution:   Add 'c' flag to 'shortmess' option. (Shougo Matsu)

runtime/doc/options.txt

@@ -6254,6 +6254,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 	  A	don't give the "ATTENTION" message when an existing swap file
 		is found.
 	  I	don't give the intro message when starting Vim |:intro|.
+	  c	don't give |ins-completion-menu| messages.  For example,
+		"-- XXX completion (YYY)", "match 1 of 2", "The only match",
+		"Pattern not found", "Back at original", etc.
 
 	This gives you the opportunity to avoid that a change between buffers
 	requires you to hit <Enter>, but still gives as useful a message as