Enable remote debugging for nova

This patch added 2 command line parameters which are used to
connect to an external debugger such as pycharm or eclipse.
This feature is used when you want to connect to a nova
service via a debugger running on a different host.
To use it you start the nova service with  the following
command line parameters

--remote_debug-host <where the debugger is running>
--remote_debug-port <port> it's listening on>.

DocImpact
Closes-bug: #1251021
Change-Id: I6ede9bf0813eafbeb91d858c297d4c160aafceba
Merge "Enable remote debugging for nova"