ini_file: prohibit section name 'default'

allow update of default section
add blurb re template to create base file

library/ini_file

@@ -74,6 +74,10 @@ examples:
 notes:
    - While it is possible to add an I(option) without specifying a I(value), this makes
      no sense.
+   - A section named C(default) cannot be added by the module, but if it exists, individual
+     options within the section can be updated. (This is a limitation of Python's I(ConfigParser).)
+     Either use M(template) to create a base INI file with a C([default]) section, or use
+     M(lineinfile) to add the missing line.
 requirements: [ ConfigParser ]
 author: Jan-Piet Mens
 '''
@@ -112,6 +116,9 @@ def do_ini(module, filename, section=None, option=None, value=None, state='prese
 
     if state == 'present':
         if cp.has_section(section) == False:
+            if section.upper() == 'DEFAULT':
+                module.fail_json(msg="[DEFAULT] is an illegal section name")
+
             cp.add_section(section)
             changed = True
 
@@ -121,6 +128,9 @@ def do_ini(module, filename, section=None, option=None, value=None, state='prese
                 if str(value) != str(oldvalue):
                     cp.set(section, option, value)
                     changed = True
+            except ConfigParser.NoSectionError:
+                cp.set(section, option, value)
+                changed = True
             except ConfigParser.NoOptionError:
                 cp.set(section, option, value)
                 changed = True