Don't autosuggest in builtin_read

https://github.com/fish-shell/fish-shell/issues/29

builtin.cpp

@@ -2327,7 +2327,9 @@ static int builtin_read( parser_t &parser, wchar_t **argv )
 			reader_set_highlight_function( &highlight_shell );
 			reader_set_test_function( &reader_shell_test );
 		}
-		
+		/* No autosuggestions in builtin_read */
+		reader_set_allow_autosuggesting(false);
+        
 		reader_set_buffer( commandline, wcslen( commandline ) );
 		proc_push_interactive( 1 );