Fix ModuleFactoryBundleTracker shutdown hang

Fix ModuleFactoryBundleTracker shutdown hang

If karaf is shutdown quickly after starting, the
ModuleFactoryBundleTracker#getModuleFactoryEntries method may
hang for a while trying to obtain BundleContexts. This has
been seen on jenkins with some feature tests. The ModuleFactoryBundleTracker
does a 1 min busy wait trying to obtain the BundleContext. This was done b/c the
tracker listens for RESOLVED bundles and the BundleContext isn't available
until after the bundle is started. So the busy wait was intended for startup
when bundles transition from RESOLVED -> STARTING. Once obtained, the
BundleContext is cached.

This works fine normally when all bundles start up. However, if stopped
quickly, some bundles may not have started, ie they remain in the
RESOLVED state with null BundleContext, so on shutdown when someone
calls getModuleFactoryEntries, it will busy wait and eventually timeout which
can take minutes.

What we need to do is remove the ModuleFactory entries when bundles are
stopped. The ModuleFactoryBundleTracker#removedBundle method does this
but it wasn't called on shutdown b/c it tracks RESOLVED, STARTING, ACTIVE
and STOPPING states. The solution is to remove STOPPING from the tracked states
so removedBundle will get called on transition ACTIVE -> STOPPING.
However, when transition STOPPING -> RESOLVED occurs the bundle will get
added back to the tracker and we don't want to re-add the ModuleFactory
entries. To prevent this it checks for BundleEvent type STOPPED.

Change-Id: I82889a682809d4217dc4253eb60c922209ad7242
Signed-off-by: Tom Pantelis <tpanteli@brocade.com>