No leap second on 2017-06-30.

Per IERS Bulletin C53 (2017-01-09), no leap second on 2017-06-30.
http://datacenter.iers.org/eop/-/somos/5Rgv/getTX/16/bulletinc-053.txt

* leap-seconds.list: Update file from NIST, retrieved from
<ftp://time.nist.gov/pub/leap-seconds.list>.

leap-seconds.list

@@ -199,10 +199,10 @@
 #	current -- the update time stamp, the data and the name of the file
 #	will not change.
 #
-#	Updated through IERS Bulletin C52
-#	File expires on:  28 June 2017
+#	Updated through IERS Bulletin C53
+#	File expires on:  28 December 2017
 #
-#@	3707596800
+#@	3723408000
 #
 2272060800	10	# 1 Jan 1972
 2287785600	11	# 1 Jul 1972
@@ -247,4 +247,4 @@
 #	the hash line is also ignored in the
 #	computation.
 #
-#h	dacf2c42 2c4765d6 3c797af8 2cf630eb 699c8c67
+#h	62cf8c5d 8bbb6dcc c61e3b56 c308343 869bb80d