Allow Atomix logging configuration to be overridden in stc tests

Change-Id: I67c4365859f380dd8c89c645b1a52f382c2595a4
diff --git a/tools/test/bin/atomix-config b/tools/test/bin/atomix-config
index f7decba..84b69fe 100755
--- a/tools/test/bin/atomix-config
+++ b/tools/test/bin/atomix-config
@@ -36,6 +36,5 @@
 atomix-gen-config $node $CDEF_FILE
 scp -q $CDEF_FILE $remote:$ATOMIX_INSTALL_DIR/atomix.json
 
-ssh -tt $ONOS_USER@$node "
-    sed -i -e $'s/<logger name=\"io.atomix\" level=\"INFO\" \/>/<logger name=\"io.atomix\" level=\"INFO\" \/>\\\n    <logger name=\"io.atomix.protocols.raft\" level=\"DEBUG\" \/>/g' /opt/atomix/conf/logback.xml
-"
+LOGBACK_FILE="$ONOS_ROOT"/tools/test/configs/atomix/logback.xml
+scp -q $LOGBACK_FILE $remote:/opt/atomix/conf/logback.xml