Fix plotting bug
Fix plotting bug

See GitHub issue #391

There has been a change in the networkx drawing API, which means
'figure' is no longer an accepted keyword argument.

Change-Id: I8600e8cd5eb2cb378a529c7857f664c1ebed8337
Signed-off-by: Jonas Mårtensson <9c18489050b439bcd0a9df0d47735ceb99443dbb@ri.se>

Telecominfraproject/gnpy