ttcn3-{ggsn,pgw}-test: Avoid open5gs itself logging to a file

We already log stdout/stderr to a file, so there's no need to log a file
internally. We prefer logging that through stdout/stderr in order to
catch more stuff, like segfaults.

Change-Id: Ifdc010f26abdc8cefeec0c72a1f617911ec375d7

ttcn3-ggsn-test/ogs/open5gs-smf.yaml

@@ -19,7 +19,6 @@
 #    domain: core,pfcp,fd,pfcp,gtp,smf,event,tlv,mem,sock
 #
 logger:
-    file: /data/open5gs-smfd.log
     level: info
 #
 # smf:

ttcn3-ggsn-test/ogs/open5gs-upf.yaml

@@ -19,7 +19,6 @@
 #    domain: core,pfcp,gtp,upf,event,tlv,mem,sock
 #
 logger:
-    file: /data/open5gs-upfd.log
     level: info
 
 #

ttcn3-pgw-test/open5gs-nrf.yaml

@@ -21,7 +21,7 @@ db_uri: mongodb://localhost/open5gs
 #    domain: core,sbi,nrf,event,mem,sock
 #
 logger:
-    file: /data/open5gs-nrfd.log
+    level: info
 
 #
 # nrf:

ttcn3-pgw-test/open5gs-smf.yaml

@@ -19,7 +19,7 @@
 #    domain: core,pfcp,fd,pfcp,gtp,smf,event,tlv,mem,sock
 #
 logger:
-    file: /data/open5gs-smfd.log
+    level: info
 #
 # smf:
 #

ttcn3-pgw-test/open5gs-upf.yaml

@@ -19,7 +19,7 @@
 #    domain: core,pfcp,gtp,upf,event,tlv,mem,sock
 #
 logger:
-    file: /data/open5gs-upfd.log
+    level: info
 
 #
 # upf: