Update unstable library feature list by Travis CI build 1534

Author: Travis CI

unstable_library_feature.txt

@@ -7,7 +7,7 @@ libstd_io_internals                 42788    2017-05-14 21:29:18 -0400  2017-05-
 read_initializer                    42788    2017-05-14 21:29:18 -0400  2017-05-14 21:29:18 -0400
 try_trait                           42327    2017-05-31 01:30:13 -0700  2017-06-07 22:12:18 -0400
 fn_traits                           29625    2017-06-07 21:59:57 -0400  2017-06-07 21:59:57 -0400
-generator_trait                     43122    2017-07-10 09:33:54 -0700  2020-01-25 20:03:10 +0100
+generator_trait                     43122    2017-07-10 09:30:57 -0700  2020-01-25 20:03:10 +0100
 drain_filter                        43244    2017-07-14 21:54:17 -0400  2017-12-09 01:09:23 -0700
 map_entry_replace                   44286    2017-09-03 20:16:20 +0200  2017-10-09 21:06:20 +0200
 deadline_api                        46316    2017-11-27 22:31:00 +0100  2017-11-27 22:31:00 +0100