next: remove duplicated targets when updating from an unstable changeset

--HG--
branch : stable
8 jobs for topic/stable/next-double in 6 minutes and 35 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed checks-py2 #192386

00:01:48

passed checks-py3 #192387

00:01:32

passed doc #192392

00:00:15

manual pytype #192385
allowed to fail manual
passed tests-py2-cext #192388

00:04:42

passed tests-py2-pure #192389

00:06:26

passed tests-py3-cext #192390

00:06:34

passed tests-py3-pure #192391

00:03:07