[cmake] Remove install of __init__.py from dynamic_graph

As dynamic-graph-python is not ready, this is breaking
the overall system.
20 jobs for devel in 45 minutes and 38 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #62742
doc-coverage

00:45:34

41.0%
passed #62743
allowed to fail
format

00:03:09

passed #62727
robotpkg-py-sot-core-v3-16.04-debug

00:31:09

passed #62724
robotpkg-py-sot-core-v3-16.04-release

00:12:05

passed #62730
robotpkg-py-sot-core-v3-18.04-debug

00:44:00

passed #62729
robotpkg-py-sot-core-v3-18.04-release

00:16:33

passed #62725
allowed to fail
robotpkg-py-sot-core-v3-py3-16.04-debug

00:12:07

passed #62726
allowed to fail
robotpkg-py-sot-core-v3-py3-16.04-release

00:12:05

passed #62731
allowed to fail
robotpkg-py-sot-core-v3-py3-18.04-debug

00:44:17

passed #62728
allowed to fail
robotpkg-py-sot-core-v3-py3-18.04-release

00:44:12

passed #62735
robotpkg-py-sot-core-v3-py3-stretch-debug

00:44:22

passed #62732
robotpkg-py-sot-core-v3-py3-stretch-release

00:44:10

passed #62733
robotpkg-py-sot-core-v3-stretch-debug

00:44:10

passed #62734
robotpkg-py-sot-core-v3-stretch-release

00:44:11

passed #62736
robotpkg-sot-core-v3-16.04-debug

00:18:00

passed #62737
robotpkg-sot-core-v3-16.04-release

00:17:59

passed #62738
robotpkg-sot-core-v3-18.04-debug

00:24:15

passed #62739
robotpkg-sot-core-v3-18.04-release

00:24:14

passed #62741
robotpkg-sot-core-v3-stretch-debug

00:24:14

passed #62740
robotpkg-sot-core-v3-stretch-release

00:24:14