[db_oracle] Print "connection dropped" at debug level

We change this to only used in debugging mode to determine if the error is a lost connection error.
The higher-level caller will prints more detailed error messages.

modules/db_oracle/dbase.c

@@ -64,7 +64,7 @@ static const char* db_oracle_errorinfo(ora_con_t* con)
 			(OraText*)errbuf, sizeof(errbuf),
 			OCI_HTYPE_ERROR) != OCI_SUCCESS) errbuf[0] = '\0';
 	else if (db_oracle_connection_lost(errcd)) {
-		LM_ERR("connection dropped\n");
+		LM_DBG("connection dropped\n");
 		db_oracle_disconnect(con);
 	}