graph_draw(): Fix inline SVG drawing with jupyter notebooks

This fixes issue #469
6 jobs for master in 203 minutes and 38 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Test
passed job_clang_amd64 #3598
amd64

03:17:28

passed job_clang_amd64_nosh #3602
amd64

02:56:30

passed job_clang_py2_amd64 #3600
amd64

03:23:38

passed job_gcc_amd64 #3597
amd64

02:44:24

passed job_gcc_amd64_nosh #3601
amd64

02:07:32

passed job_gcc_py2_amd64 #3599
amd64

02:40:37