Update comment

src/lib/ee_lib_stack_packages.sh

@@ -14,7 +14,8 @@ function ee_lib_stack_packages()
 
 				# Log only single time
 				# ee site create example.com called ee stack install nginx
-				# So in log file all logs written twice
+				# So when ee stack install nginx run in sub-shell the value of EE_COMMAND_LOG=/dev/null
+				# So in log file all logs written single time only
 				export EE_LOG=false
 
 				# The following command creates its own sub-shell