Use Felix DM for OVSDB Neutron Services

The ovsdb.neutron bundle has serveral services currently implemented as
singletons. This makes these classes difficult to test and also creates
a hard coded dependency. We can use the Felix DM provided by the OSGi
container to implement dependency injection for these services.
Fixes bug 1030

Change-Id: Ia0dca98302e3f0b6745c1687db9f0717c2b6b558
Signed-off-by: Dave Tucker <djt@redhat.com>