Make CliInstaller control the processing logic of the error

Make CliInstaller control the processing logic of the error

Previously, if there was an error during CLI installation,
CliInstaller::showStatusMessage() exited the script directly. The exit
timing of the script should be given to the caller, not the callee.
So, I coding:
[1] Remove `exit()` from CliInstaller::showStatusMessage()
[2] Make the callee to return Status, the caller determine how to handle these Status
[3] Strictly check the key database type instead of just outputting message

Bug: T46511
Change-Id: I72ffd33fe5c592b9ea78f37bae5a9c081295c624