This patch completes the ThemeManagerTest and thus brings the themes
package to 100% test coverage! \o/
Change-Id: I3bdb41781f127c9554c83f56503d591371031a23
TICKET: CYNGNOS-3029
This fixes the assmption that a device will have a default theme
declared in CMSettings, which is not always the case. If no default
theme package is defined in CMSettings we use ThemeConfig.SYSTEM_DEFAULT
instead.
Change-Id: If7952ea984eea0accf3d0990871fb11e3ccc373a