addons: bridge: move the default running_pvid assignment to before

addons: bridge: move the default running_pvid assignment to before
pvid_to_del is calculated

Ticket: CM-12355
Reviewed By: julien, nikhil
Testing Done: tested with failing config

My previous fix for the same bug did not fix the problem completly.
In this patch all running pvid calculation
is done before the pvid_to_del is calculated.
This makes sure the old pvid is deleted if it is not
the same as current pvid in all cases

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>