rspro_client_fsm: Disable automatic connect on FSM allocation

So far, the rspor_client_fsm immediately attempted to establish a
TCP connection to the RSPRO server when calling server_conn_fsm_alloc().

Let's make this implicit auto-connect an explicit request to connect
using the newly-introduced SRVC_E_ESTABLISH.

Let's also change all three existing users of server_conn_fsm_alloc()
to send SRVC_E_ESTABLISH after calling it.

The rationale of this change is to use the same rspro_client_fsm also
for the client->bankd RSPRO connection, where we don't want to
automatically connect at startup, but connect only at a later point, after the
server a has told us to do so.

Change-Id: Icd882405f2ef54e10a66054829c089e4985f1d1f
diff --git a/src/rspro_client_fsm.h b/src/rspro_client_fsm.h
index 8e7f58c..c11e260 100644
--- a/src/rspro_client_fsm.h
+++ b/src/rspro_client_fsm.h
@@ -5,6 +5,7 @@
 #include <osmocom/rspro/RsproPDU.h>
 
 enum server_conn_fsm_event {
+	SRVC_E_ESTABLISH,	/* instruct SRVC to (re)etablish TCP connection to bankd */
 	SRVC_E_TCP_UP,
 	SRVC_E_TCP_DOWN,
 	SRVC_E_KA_TIMEOUT,