Before running client in off-line mode, attempt to socket-activate the server

Before running client in off-line mode, attempt to socket-activate the server

Security-manager is started by systemd on socket-activation basis. This
means that it won't start unless a client connects to its socket. But
client library attempts to detect off-line mode by checking whether the
service is already running. This leads to erroneous off-line runs when in
fact a message should be sent over socket to activate the service.

This change adds one more step to off-line mode detection. When the service
isn't running, client will send a special NOOP message over socket.
If systemd manages to activate security-manager service, normal on-line
operation is then performed.

Change-Id: I94b1b10af24e3b90d048fe1b96b8d870da785d8b
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>