Detect bug 5014

Detect bug 5014

Netconf gained another bad habit. It appears to be down until
the user tries to configure a device, then it wakes up and
starts to be visible.

This bad habit was reported as bug 5014 as it breaks the
Netconf readiness suite (and probably other production
workflows that depend on the ability to determine when
Netconf becomes available). This adds a test case that
detects this bug by trying to configure a dummy device when
Netconf appears to be down after the wait is completed.
If Netconf mysteriously raises from the dead, the test case
fails, reporting that bug 5014 was found.

Change-Id: I29e8be136aaddaa13169b533805415729fcc4959
Signed-off-by: Jozef Behran <jbehran@cisco.com>