The pattern to use 'with' to keep a CTRL connection open adds indents to
every test script that wants to avoid multiple reconnections to the
CTRL. Instead, keeping a single open connection that is cleaned up on
{bsc,msc,nitb} object cleanup ensures that a) the program started up
successfully and opened a CTRL port, b) always has a CTRL open without
having to worry about it and c) keeps test scripts less
complex/indented/crufted.
(These are all current users of the OsmoCtrl API.)
Change-Id: I53fedbe569c5ccbc4b1a17dafe1f8d1bb8200b24