[Code formatting: Change indentation style to space](https://github.com/clicon/clixon/issues/379)

* Applies to all c/h/y/l/sh files and .editorconfig

test/test_feature_startup.sh

@@ -65,7 +65,7 @@ testrun()
     new "kill old backend"
     sudo clixon_backend -zf $cfg
     if [ $? -ne 0 ]; then
-	err
+        err
     fi
 
     new "start backend -s startup -f $cfg"
@@ -88,7 +88,7 @@ if [ $BE -ne 0 ]; then
     new "kill old backend"
     sudo clixon_backend -zf $cfg
     if [ $? -ne 0 ]; then
-	err
+        err
     fi
     # kill backend
     stop_backend -f $cfg