Allow SCS to launch without any container
Allow SCS to launch without any container

[Bug]           SCS segfaulted when launching without any containers provided in config.
[Cause]         Some functions assumed that certain config fields should never be empty
[Solution]      Additional checks to avoid segfault.
[Verification]  Build, install, run tests, launch SCS without any predefined containers.
                Try to switch between containers when less than two containers are present.

Change-Id: I58a69d55807f686fb168057dfb1b447707351a46

Samsung/vasum,Samsung/vasum,Samsung/vasum,Samsung/vasum