{enb,epc,ms}_srs: expose log.all_level parameter

expose paramter to set log level, use warning as default

Change-Id: I4e77e5351399aefef47a309c82b8805e2c6022c5
diff --git a/src/osmo_gsm_tester/obj/ms_srs.py b/src/osmo_gsm_tester/obj/ms_srs.py
index 57721ac..04df1ba 100644
--- a/src/osmo_gsm_tester/obj/ms_srs.py
+++ b/src/osmo_gsm_tester/obj/ms_srs.py
@@ -47,6 +47,7 @@
 
     config_schema = {
         'enable_pcap': schema.BOOL_STR,
+        'log_all_level': schema.STR,
         }
     schema.register_config_schema('modem', config_schema)