FEATURE: Ingest expanded VSDs (in addition to added VSDs)

[iczerjones]

Presently autolvm will ingest and incorporate any added VSDs into the target volume. Investigate adding detection and ingest of expanded VSDs as well.

Present behavior:

• Add VSD -> Volume is expanded using new VSD
• Expand existing VSD -> No change to volume

Expected behavior:

• Add VSD -> Volume is expanded using new VSD
• Expand existing VSD -> Volume is expanded using the new capacity