beta: fix scap for videoscalers

Restores the beta::common and beta::scap::target classes to
videoscalers in beta. These classes were removed by the refactoring in
I2d19838c173441ced72d51074ea22bc0cbbcfc8f

Change-Id: I54d471497c5785ddd589418aecd26b9f2cae655c
Merge "beta: fix scap for videoscalers" into production