Insert a new line before a section name

A minus at the end of a block prevents whitespace to be added.
In this particular case a new line between the last parameter in a section
and the next section is ommitted. The result looks like this:

[Section1]
Param1=Value
Param2=Value[Section2]
Param3=Value

Change-Id: I9faba3857f46f70ec0ddc380e6b84f72a5dc16e4

linux/files/systemd.conf

 {%- from "linux/map.jinja" import system with context -%}
-{%- for section, options in settings.iteritems() -%}
+{%- for section, options in settings.iteritems() %}
 [{{ section }}]
 {%- for option, value in options.iteritems() %}
 {{ option }}={{ value }}