This patch changes the OVN module from DevStack to allow for using the
OSapackaged version of OVN instead of compiling it from source.
A new variable called OVN_BUILD_FROM_SOURCE has been introduced and when
set to False (the default value) OVN will then use the packaged version
for setting up DevStack.
Note, in the stop_ovn() function, the OVN metadata agent service name
was wrong and the service wasn't being stopped as part of ./unstack.sh.
This patch also fixed it as well.
Change-Id: Ib41e3b486550200572afd6b3ba783d7644d70d44
Signed-off-by: Lucas Alvares Gomes <lucasagomes@gmail.com>
Co-Authored-By: Slawek Kaplonski <skaplons@redhat.com>