CustomChoiceList: Increment min-sdk to 4

Resolves build error:
    Manifest merger failed : uses-sdk:minSdkVersion 3 cannot be
    smaller than version 4 declared in library
    com.android.support:support-v4:21.0.0

Change-Id: Id1195405276e993200e8a326ef63b15c8261bb6d
1 file changed