srs{ue,enb,epc}: Disable pcap by default, allow enabling by param

Take the change to fix several small things and support recording pcap
in srsENB.

pcap generation can be enabled with scenario cfg-srs-enable-pcap.

Change-Id: Ia096a9be7efb2123f95115c751e2402fb4fec935
diff --git a/src/osmo_gsm_tester/resource.py b/src/osmo_gsm_tester/resource.py
index cdf0596..8a93ea4 100644
--- a/src/osmo_gsm_tester/resource.py
+++ b/src/osmo_gsm_tester/resource.py
@@ -116,7 +116,11 @@
 CONF_SCHEMA = util.dict_add(
     { 'defaults.timeout': schema.STR,
       'config.bsc.net.codec_list[]': schema.CODEC,
-      'config.epc.rlc_drb_mode': schema.LTE_RLC_DRB_MODE, },
+      'config.enb.enable_pcap': schema.BOOL_STR,
+      'config.epc.rlc_drb_mode': schema.LTE_RLC_DRB_MODE,
+      'config.epc.enable_pcap': schema.BOOL_STR,
+      'config.modem.enable_pcap': schema.BOOL_STR,
+    },
     dict([('resources.%s' % key, val) for key, val in WANT_SCHEMA.items()]),
     dict([('modifiers.%s' % key, val) for key, val in WANT_SCHEMA.items()]))