download-unpacked: drop unused `environment-section` option

It was partially broken since commit 8a9e3766:
it only works when combined with `environment` option.

slapos/recipe/__init__.py

@@ -43,18 +43,11 @@ def rmtree(path):
 
 class EnvironMixin(object):
 
-  def __init__(self, allow_none=True, compat=False):
+  def __init__(self, allow_none=True):
     environment = self.options.get('environment')
     if environment:
       if '=' in environment:
         self._environ = env = {}
-        if compat: # for slapos.recipe.cmmi
-          environment_section = self.options.get('environment-section')
-          if environment_section:
-            env.update(self.buildout[environment_section])
-          compat = set(env)
-        else:
-          compat = ()
         for line in environment.splitlines():
           line = line.strip()
           if line:
@@ -64,9 +57,6 @@ class EnvironMixin(object):
               raise UserError('Line %r in environment is incorrect' % line)
             k = k.rstrip()
             if k in env:
-             if k in compat:
-              compat.remove(k)
-             else:
               raise UserError('Key %r is repeated' % k)
             env[k] = v.lstrip()
       else:

slapos/recipe/downloadunpacked.py

@@ -53,7 +53,7 @@ class Recipe(EnvironMixin):
     options['location'] = \
     options['target'] = shared.location
 
-    EnvironMixin.__init__(self, True, True)
+    EnvironMixin.__init__(self, True)
 
   def install(self):
     return self._shared.install(self._install)